Uplink power sharing in dual connectivity

ABSTRACT

Systems and methods enabling uplink power sharing for dual connectivity are disclosed. Embodiments are described herein in which a maximum Uplink (UL) power on each link is configured statically, semi-statically, or dynamically. In general, regardless of the embodiment, uplink power for uplink transmissions from a wireless device on two simultaneous links is controlled such that the total uplink power does not exceeds a maximum UL transmission power level while, in some embodiments, taking into account priorities of the two links and/or priorities of various uplink channels transmitted by the wireless device on the two links. Notably, while the embodiments described herein focus on dual connectivity, the embodiments described herein can easily be extended to any number of two or more simultaneous links.

RELATED APPLICATIONS

This application claims the benefit of Patent Cooperation Treaty (PCT)application serial number PCT/CN2014/073678, filed Mar. 19, 2014, thedisclosure of which is hereby incorporated herein by reference in itsentirety.

TECHNICAL FIELD

This disclosure pertains to dual connectivity in Long Term Evolution(LTE) wireless networks.

BACKGROUND

Long Term Evolution (LTE) uses Orthogonal Frequency DivisionMultiplexing (OFDM) in the downlink and Discrete Fourier Transform(DFT)-spread OFDM in the uplink. The basic LTE downlink physicalresource can thus be seen as a time-frequency grid as illustrated inFIG. 1 where each resource element corresponds to one OFDM subcarrierduring one OFDM symbol interval. In the time domain, LTE downlinktransmissions are organized into radio frames of 10 milliseconds (ms),where each radio frame includes ten equally-sized subframes of lengthT_(subframe)=1 ms. FIG. 2 is a schematic diagram of an LTE time-domainstructure.

Resource allocation in LTE is typically described in terms of resourceblocks, where a resource block corresponds to one slot (0.5 ms) in thetime domain and 12 contiguous subcarriers in the frequency domain. Apair of two adjacent resource blocks in time (1.0 ms) is known as aresource block pair. Resource blocks are numbered in the frequencydomain, starting with 0 from one end of the system bandwidth.

The notion of Virtual Resource Blocks (VRBs) and Physical ResourceBlocks (PRBs) has been introduced in LTE. The actual resource allocationto a User Equipment device (UE) is made in terms of VRB pairs. There aretwo types of resource allocations, localized and distributed. In thelocalized resource allocation, a VRB pair is directly mapped to a PRBpair, hence two consecutive and localized VRBs are also placed asconsecutive PRBs in the frequency domain. On the other hand, distributedVRBs are not mapped to consecutive PRBs in the frequency domain, therebyproviding frequency diversity for the data channel transmitted usingthese distributed VRBs.

Downlink transmissions are dynamically scheduled in LTE. In particular,in each subframe, the base station transmits control informationpertaining to which terminals, or UEs, data is transmitted and uponwhich resource blocks the data is transmitted in a downlink subframe.This control signaling is typically transmitted in the first 1, 2, 3, or4 OFDM symbols in each subframe, and the number n=1, 2, 3, or 4 is knownas the Control Format Indicator (CFI). The downlink subframe alsocontains Common Reference Symbols (CRS), which are known to the receiverand used for coherent demodulation of, for example, the controlinformation. A downlink system with CFI=3 OFDM symbols as control isillustrated in FIG. 3.

From LTE Release 11 onwards, the above described resource assignmentscan also be scheduled on the enhanced Physical Downlink Control Channel(ePDCCH). For Release 8 to Release 10, only the Physical DownlinkControl Channel (PDCCH) is available. The PDCCH is used to carryDownlink Control Information (DCI) such as scheduling decisions andpower-control commands. More specifically, the DCI includes downlinkscheduling assignments, uplink scheduling grants, and power controlcommands. In particular, downlink scheduling assignments includePhysical Downlink Shared Channel (PDSCH) resource indication, transportformat, Hybrid Automatic Repeat Request (HARQ) information, and controlinformation related to spatial multiplexing (if applicable). A downlinkscheduling assignment also includes a command for power control of thePhysical Uplink Control Channel (PUCCH) used for transmission of HARQacknowledgements in response to downlink scheduling assignments. Uplinkscheduling grants include Physical Uplink Shared Channel (PUSCH)resource indication, transport format, and HARQ-related information. Anuplink scheduling grant also includes a command for power control of thePUSCH. Power control commands included in the DCI include power controlcommands for a set of terminals, or UEs, as a complement to the commandsincluded in the scheduling assignments/grants.

One PDCCH carries one DCI message with one of the formats above. Asmultiple terminals can be scheduled simultaneously, on both downlink anduplink, there must be a possibility to transmit multiple schedulingmessages within each subframe. Each scheduling message is transmitted ona separate PDCCH, and consequently there are typically multiplesimultaneous PDCCH transmissions within each cell. Furthermore, tosupport different radio channel conditions, link adaptation can be used,where the code rate of the PDCCH is selected to match the radio channelconditions.

To allow for simple yet efficient processing of the control channels inthe terminal, the mapping of PDCCHs to resource elements is subject to acertain structure. This structure is based on Control Channel Elements(CCEs), which consists of nine Resource Element Groups (REGs). Thenumber of CCEs, one, two, four, or eight, required for a certain PDCCHdepends on the payload size of the control information (DCI payload) andthe channel coding rate. This is used to realize link adaptation for thePDCCH; if the channel conditions for the terminal to which the PDCCH isintended are disadvantageous, a larger number of CCEs needs to be usedcompared to the case of advantageous channel conditions. The number ofCCEs used for a PDCCH is also referred to as the Aggregation Level (AL).

The network can then select different aggregation levels and PDCCHpositions for different UEs from the available PDCCH resources. For eachPDCCH, as illustrated in FIG. 4, a Cyclic Redundancy Check (CRC) isattached to each DCI message payload. The identity of the terminal (orterminals) addressed—that is, the Radio Network Temporary Identifier(RNTI)—is included in the CRC calculation and not explicitlytransmitted. Depending on the purpose of the DCI message (unicast datatransmission, power control command, random access response, etc.),different RNTIs are used; for normal unicast data transmission, theterminal-specific Cell RNTI (C-RNTI) is used. After CRC attachment, thebits are coded with a rate −1/3 tail-biting convolutional code andratematched to fit the amount of resources used for PDCCH transmission.After the PDCCHs to be transmitted in a given subframe have beenallocated to the desired resource elements (the details of which aregiven below), the sequence of bits corresponding to all the PDCCHresource elements to be transmitted in the subframe, including theunused resource elements, is scrambled by a cell- and subframe-specificscrambling sequence to randomize inter-cell interference, followed byQuadrature Phase Shift Keying (QPSK) modulation and mapping to resourceelements. The entire collection of the REGs (including those unused byany PDCCH) is then interleaved across the entire control region torandomize inter-cell interference as well as capturing frequencydiversity for the PDCCHs.

LTE defines so-called PDCCH search spaces, which describe the set ofCCEs the terminal is supposed to monitor for schedulingassignments/grants relating to a certain component carrier. A searchspace is a set of candidate control channels formed by CCEs on a givenaggregation level, which the terminal is supposed to attempt to decode.As there are multiple aggregation levels, corresponding to one, two,four, and eight CCEs, a terminal has multiple search spaces. In eachsubframe, the terminals will attempt to decode all the PDCCHs that canbe formed from the CCEs in each of its search spaces. If the CRC checks,the content of the control channel is declared as valid for thisterminal and the terminal processes the information (schedulingassignment, scheduling grants, etc.). Each terminal in the systemtherefore has a terminal-specific search space at each aggregationlevel.

In several situations, there is a need to address a group of, or all,terminals in the system. To allow all terminals to be addressed at thesame time, LTE has defined common search spaces in addition to theterminal-specific search spaces. A common search space is, as the nameimplies, common, and all terminals in the cell monitor the CCEs in thecommon search spaces for control information. Although the motivationfor the common search space is primarily transmission of various systemmessages, it can be used to schedule individual terminals as well. Thus,it can be used to resolve situations where scheduling of one terminal isblocked due to lack of available resources in the terminal-specificsearch space. More important, the common search space is not dependentof UE configuration status. Therefore, the common search space can beused when the network needs to communicate with the UE during UEreconfiguration periods. FIG. 5 is a schematic diagram illustratingcommon and UE-specific search spaces for two UEs.

With regard to PUCCH, if a terminal has not been assigned an uplinkresource for data transmission, the L1/L2 control information (channelstatus reports, HARQ acknowledgments, and scheduling requests) istransmitted in uplink resources (resource blocks) specifically assignedfor uplink L1/L2 control on LTE Release 8 PUCCH. As illustrated in FIG.6, these resources are located at the edges of the total available cellbandwidth. Each such resource consists of 12 “subcarriers” (one resourceblock) within each of the two slots of an uplink subframe. In order toprovide frequency diversity, these frequency resources are frequencyhopping on the slot boundary, i.e., one “resource” consists of 12subcarriers at the upper part of the spectrum within the first slot of asubframe and an equally sized resource at the lower part of the spectrumduring the second slot of the subframe or vice versa. If more resourcesare needed for the uplink L1/L2 control signaling, e.g. in case of verylarge overall transmission bandwidth supporting a large number of users,additional resource blocks can be assigned next to the previouslyassigned resource blocks.

LTE Release 10 (and subsequent releases of the LTE standard) supportsbandwidths larger than 20 megahertz (MHz). One important requirement inLTE Release 10 is to assure backward compatibility with LTE Release 8.This should also include spectrum compatibility. That would imply thatan LTE Release 10 carrier, wider than 20 MHz, should appear as a numberof LTE carriers to an LTE Release 8 terminal. Each such carrier can bereferred to as a Component Carrier (CC). In particular, for early LTERelease 10 deployments, it can be expected that there will be a smallernumber of LTE Release 10-capable terminals compared to many LTE legacyterminals. Therefore, it is necessary to assure an efficient use of awide carrier also for legacy terminals, i.e., that it is possible toimplement carriers where legacy terminals can be scheduled in all partsof the wideband LTE Release 10 carrier. The straightforward way toobtain this would be by means of Carrier Aggregation (CA). CA impliesthat an LTE Release 10 terminal can receive multiple CCs, where the CCshave, or at least the possibility to have, the same structure as a LTERelease 8 carrier. CA is illustrated in FIG. 7.

The number of aggregated CCs as well as the bandwidth of the individualCCs may be different for uplink and downlink. A symmetric configurationrefers to the case where the number of CCs in downlink and uplink is thesame whereas an asymmetric configuration refers to the case that thenumber of CCs is different. It is important to note that the number ofCCs configured in a cell may be different from the number of CCs seen bya terminal. A terminal may, for example, support more downlink CCs thanuplink CCs, even though the cell is configured with the same number ofuplink and downlink CCs.

During initial access, an LTE Release 10 terminal behaves similar to aLTE Release 8 terminal. Upon successful connection to the network, aterminal may—depending on its own capabilities and the network—beconfigured with additional CCs in the uplink and the downlink.Configuration is based on Radio Resource Control (RRC). Due to the heavysignaling and rather slow speed of RRC signaling, it is envisioned thata terminal may be configured with multiple CCs even though not all ofthem are currently used. If a terminal is configured on multiple CCs,this would imply that the terminal has to monitor all downlink CCs forPDCCH and PDSCH. This implies a wider receiver bandwidth, highersampling rates, etc. resulting in high power consumption.

To mitigate above problems, LTE Release 10 supports activation of CCs ontop of configuration. The terminal monitors only configured andactivated CCs for PDCCH and PDSCH. Because activation is based on MediumAccess Control (MAC) control elements—which are faster than RRCsignaling—activation/de-activation can follow the number of CCs that arerequired to fulfill the current data rate needs. Upon arrival of largedata amounts, multiple CCs are activated, used for data transmission,and de-activated if not needed anymore. All but one CC—the DownlinkPrimary CC (DL PCC)—can be de-activated. Therefore, activation providesthe possibility to configure multiple CCs but only activate them asneeded. Most of the time, a terminal would have one or very few CCsactivated, resulting in a lower reception bandwidth and thus batteryconsumption.

Scheduling of a CC is done on the PDCCH via downlink assignments.Control information on the PDCCH is formatted as a DCI message. In LTERelease 8, a terminal only operates with one downlink and one uplink CCand, as such, the association between downlink assignment, uplinkgrants, and the corresponding downlink and uplink CCs is clear. In LTERelease 10, two modes of CA need to be distinguished. The first mode isvery similar to the operation of multiple LTE Release 8 terminals wherea downlink assignment or an uplink grant contained in a DCI messagetransmitted on a CC is either valid for the downlink CC itself or for anassociated (either via cell-specific or UE specific linking) uplink CC.The second mode augments a DCI message with the Carrier Indicator Field(CIF). A DCI containing a downlink assignment with CIF is valid for thatdownlink CC indicted with CIF, and a DCI containing an uplink grant withCIF is valid for the indicated uplink CC.

DCI messages for downlink assignments contain, among other things,resource block assignment, modulation and coding scheme relatedparameters, HARQ redundancy version, etc. In addition to thoseparameters that relate to the actual downlink transmission, most DCIformats for downlink assignments also contain a bit field for TransmitPower Control (TPC) commands. These TPC commands are used to control theuplink power control behavior of the corresponding PUCCH that is used totransmit the HARQ feedback.

In LTE Release 10, the transmission of PUCCH is mapped onto one specificuplink CC, the Uplink Primary CC (UL PCC). Terminals only configuredwith a single downlink CC (which is then the DL PCC) and uplink CC(which is then the UL PCC) are operating dynamicAcknowledgement/Non-Acknowledgement (ACK/NACK) on PUCCH according to LTERelease 8. The first CCE used to transmit PDCCH for the downlinkassignment determines the dynamic ACK/NACK resource on LTE Release 8PUCCH. Since only one downlink CC is cell-specifically linked with theUL PCC, no PUCCH collisions can occur since all PDCCHs are transmittedusing different first CCE.

Upon reception of downlink assignments on a single Secondary CC (SCC) orreception of multiple downlink assignments, CA PUCCH should be used. Adownlink SCC assignment alone is untypical. The enhanced or evolved NodeB (eNB) scheduler should strive to schedule a single downlink CCassignment on the DL PCC and try to de-activate SCCs if not needed. Apossible scenario that may occur is that an eNB schedules a terminal onmultiple downlink CCs including the PCC. If the terminal misses all butthe DL PCC assignment, the terminal will use LTE Release 8 PUCCH insteadof CA PUCCH. To detect this error case, the eNB has to monitor both theLTE Release 8 PUCCH and the CA PUCCH.

In LTE Release 10, the CA PUCCH format is based on the number ofconfigured CCs. Configuration of CCs is based on RRC signaling. Aftersuccessful reception/application of the new configuration, aconfirmation message is sent back making RRC signaling very safe.

Transmission and reception from a node, e.g. a terminal in a cellularsystem such as LTE, can be multiplexed in the frequency domain or in thetime domain (or combinations thereof). Frequency Division Duplex (FDD),as illustrated on the left in FIG. 8, implies that downlink and uplinktransmission take place in different, sufficiently separated, frequencybands. Time Division Duplex (TDD), as illustrated on the right in FIG.8, implies that downlink and uplink transmission take place indifferent, non-overlapping time slots. Thus, TDD can operate in unpairedspectrum, whereas FDD requires paired spectrum. Typically, the structureof the transmitted signal in a communication system is organized in theform of a frame structure. For example, LTE uses ten equally-sizedsubframes of length 1 ms per radio frame as illustrated in FIG. 9.

In case of FDD operation (upper part of FIG. 9), there are two carrierfrequencies, one for uplink transmission (f_(UL)) and one for downlinktransmission (f_(DL)). At least with respect to the terminal in acellular communications system, FDD can be either full duplex or halfduplex. In the full duplex case, a terminal can transmit and receivesimultaneously, while in half duplex operation, the terminal cannottransmit and receive simultaneously (the base station is capable ofsimultaneous reception/transmission though, e.g. receiving from oneterminal while simultaneously transmitting to another terminal). In LTE,a half duplex terminal is monitoring/receiving in the downlink exceptwhen explicitly being instructed to transmit in a certain subframe.

In case of TDD operation (lower part of FIG. 9), there is only a singlecarrier frequency, and uplink and downlink transmissions are alwaysseparated in time also on a cell basis. As the same carrier frequency isused for uplink and downlink transmission, both the base station and themobile terminals need to switch from transmission to reception and viceversa. An essential aspect of any TDD system is to provide thepossibility for a sufficiently large guard time where neither downlinknor uplink transmissions occur. This is required to avoid interferencebetween uplink and downlink transmissions. For LTE, this guard time isprovided by special subframes (subframe 1 and, in some cases, subframe6), which are split into three parts: a downlink part (DwPTS), a guardperiod (GP), and an uplink part (UpPTS). The remaining subframes areeither allocated to uplink or downlink transmission.

TDD allows for different asymmetries in terms of the amount of resourcesallocated for uplink and downlink transmission, respectively, by meansof different downlink/uplink configurations. In LTE, there are sevendifferent configurations as shown in FIG. 10. Note that in thedescription below, downlink subframe can mean either downlink or thespecial subframe.

To avoid severe interference between downlink and uplink transmissionsbetween different cells, neighbor cells should have the samedownlink/uplink configuration. If this is not done, uplink transmissionin one cell may interfere with downlink transmission in the neighboringcell (and vice versa) as illustrated in FIG. 11. Hence, thedownlink/uplink asymmetry can typically not vary between cells, but issignaled as part of the system information and remains fixed for a longperiod of time.

A dual connectivity framework is currently being considered for LTERelease 12. Dual connectivity refers to the operation where a given UEconsumes radio resources provided by at least two different networkpoints (master and secondary eNBs) connected with non-ideal backhaulwhile in RRC_CONNECTED. A UE in dual connectivity maintains simultaneousconnections, or links, to anchor and booster nodes, where the anchornode is also called the Master eNB (MeNB) and the booster node is alsocalled the Secondary eNB (SeNB). As the name implies, the anchor nodeterminates the control plane connection towards the UE and is thus thecontrolling node of the UE. The UE also reads system information fromthe anchor. In addition to the anchor, the UE may be connected to one orseveral booster nodes for added user plane support. The MeNB and theSeNB are connected via the Xn interface, which is currently selected tobe the same as the X2 interface between two eNBs.

The anchor and booster roles are defined from a UE point of view. Thismeans that a node that acts as an anchor to one UE may act as booster toanother UE. Similarly, though the UE reads the system information fromthe anchor node, a node acting as a booster to one UE may or may notdistribute system information to another UE. A MeNB operates to providesystem information and terminate the control plane. In addition, theMeNB may terminate the user plane. Conversely, a SeNB operates toterminate only the user plane.

In one application, dual connectivity allows a UE to connect to twonodes in order to receive data from both of these nodes to increase theUE's data rate. This user plane aggregation achieves similar benefits asCA using network nodes that are not connected by low-latencybackhaul/network connection. Due to this lack of low-latency backhaul,the scheduling and HARQ-ACK feedback from the UE to each of the nodeswill be performed separately. That is, it is expected that the UE shallhave two uplink transmitters to transmit uplink control and data to theconnected nodes.

Uplink power control controls the transmit power of the different uplinkphysical channels. As an example, if the UE transmits PUSCH without asimultaneous PUCCH for the serving cell c, then the UE transmit powerfor PUSCH transmission in subframe i for the serving cell c is given (inmilli-decibels (dBm)) by

${{P_{{PUSCH},c}(i)} = {\min \begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\{{10\; {\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\_ PUSCH},c}(j)} + {{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{Bmatrix}}},$

where:

-   -   P_(CMAX,c)(i) is the configured UE transmit power defined in        3GPP Technical Specification (TS) 36.101 V12.2.0 in subframe i        for serving cell c and {circumflex over (P)}_(CMAX,c)(i) is the        linear value of P_(CMAX,c)(i),    -   M_(PUSCH,c)(i) is the bandwidth of the PUSCH resource assignment        expressed in number of resource blocks valid for subframe i and        serving cell c,    -   P_(O) _(_) _(PUSCH,c)(j) is a desired received power level per        resource block for the serving cell c,    -   α_(c)(j) is a parameter that can take a value smaller than or        equal to 1, which allows for partial path-loss compensation.    -   PL_(c) is the downlink pathloss estimate calculated in the UE        for serving cell c in decibels (dB), where        PL_(c)=referenceSignalPower−higher layer filtered Reference        Signal Received Power (RSRP), where referenceSignalPower is        provided by higher layers and RSRP is defined in 3GPP TS 36.214        V12.0.0 for the reference serving cell and the higher layer        filter configuration is defined in 3GPP TS 36.331 V12.0.0 for        the reference serving cell.    -   Δ_(TF,c)(i) is a power offset for the specific modulation and        coding scheme of the PUSCH, and    -   f_(c)(i) is the adjustment by power control commands.

If the total transmit power of the UE would exceed {circumflex over(P)}_(CMAX)(i), the UE scales {circumflex over (P)}_(PUSCH,c)(i) for theserving cell c in subframe i such that the condition

${\sum\limits_{c}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {{{\hat{P}}_{CMAX}(i)} - {{\hat{P}}_{PUCCH}(i)}} \right)$

is satisfied where {circumflex over (P)}_(PUCCH)(i) is the linear valueof P_(PUCCH)(i), {circumflex over (P)}_(PUSCH,c)(i) is the linear valueof P_(PUSCH,c)(i), {circumflex over (P)}_(CMAX)(i) is the linear valueof the UE total configured maximum output power P_(CMAX) defined in 3GPPTS 36.101 V12.2.0 in subframe i, and w(i) is a scaling factor of{circumflex over (P)}_(PUSCH,c)(i) for serving cell c where 0≦w(i)≦1. Incase there is no PUCCH transmission in subframe i, {circumflex over(P)}_(PUCCH)(i)=0.

Currently, there is no systematic solution for addressing the uplinkpower control problem when a UE is configured with dual connectivity. Inparticular, without full knowledge of uplink transmission of the otherlink, the MeNB and the SeNB may each expect the UE to use a high uplinkpower level, which in aggregate exceeds the maximum power the UE canuse. There is no existing solution that enables the UE to allocateuplink power intelligently across two links when operating under powerconstraints. FIG. 12 is a schematic diagram illustrating uplink powerfor a MeNB and a SeNB exceeding a maximum allowed amount.

Further, differences between the characteristics of dual connectivityand those of CA pose challenges to uplink power control for both theeNBs and the UE when configured with dual connectivity. In particular,dual connectivity is similar to CA with multiple Timing Advance Groups(TAGs) in that the UE is simultaneously connected to two (or more)Transmission Points (TPs) that can be geographically separated. Thereare potentially two (or more) simultaneous downlink transmissions andtwo (or more) uplink transmissions for a given UE. However, the dualconnectivity scenario is different from CA in several aspects.

First, in dual connectivity, the MeNB and the SeNB are allowed to beconnected via a variety of backhaul links, including non-ideal backhaullinks with up to 60 ms delay. In contrast, in CA, the TPs are assumed tobe connected via ideal backhaul links, where delay is negligible overthe X2 interface. In CA, it is assumed that the TPs have a centralprocessing unit, which is not the case in dual connectivity. Second, indual connectivity, the network node's MeNB and SeNB may or may not besynchronized (synchronized network or unsynchronized network).Synchronization by Global Navigation Satellite System (GNSS) orsynchronization over backhaul network is not always available for smallcell deployments, e.g., indoor deployment or hotspots with highbuildings around. In certain deployment scenarios, it may not befeasible to synchronize the MeNB and the SeNB because the carrierfrequencies that they deploy require different synchronization sources.For example, this is the case if both the MeNB and the SeNB use TDD, andthe neighboring systems have different synchronization. Thus thedownlink subframe boundary of the MeNB and the SeNB may or may not bealigned in time. In contrast, in CA, the network nodes are assumed to besynchronized.

Third, combining the effect of unsynchronized network and timingadvance, the uplink subframe boundary misalignment, from a UE'sperspective, can be up to the maximum of 7 OFDM symbols (0.5 ms). Incontrast, in a CA scenario, the uplink subframe misalignment is only dueto the effect of timing advance, and is considered to be limited to amaximum of ˜30 microseconds (μs) plus the additional synchronizationerror of the two TPs. This corresponds to about a half OFDM symbol.Fourth, in dual connectivity, each eNB (MeNB and SeNB) operates its ownRadio Link Control (RLC), MAC (including scheduler), and physical layer.The MeNB and the SeNB independently schedule their own uplink anddownlink transmissions. Thus, for example, the UE may have twosimultaneous uplink transmissions scheduled, one by the MeNB, the otherby the SeNB, without one eNB being aware of the scheduling informationof the other eNB. Scheduling of PUCCH/PUCCH/Physical Random AccessChannel (PRACH)/Sounding Reference Signal (SRS) of one link is not knownto eNB of the other link. In contrast, in CA, a single MAC (including ascheduler) controls the multiple transmission points and has fullknowledge of the scheduled transmission of a given UE.

Fifth, in dual connectivity, at least one cell in the SeNB has aconfigured uplink and one of them is configured with PUCCH resources.Thus, a UE may be required to transmit two PUCCHs simultaneously, onetowards the MeNB, the other towards the SeNB. Two sets of Uplink ControlInformation (UCI) may be simultaneously transmitted via PUCCH (or PUSCH)on the MeNB link and the SeNB link. In contrast, in CA, UCI is onlytransmitted on one serving cell (the Primary Cell (PCell)). Sixth, indual connectivity, PRACH may be transmitted on both linkssimultaneously. In contrast, in CA a PRACH is only transmitted on onecomponent carrier at a time.

These differences pose challenges to the uplink power control mechanismfor both the eNBs and the UE when configured with dual connectivity. Assuch, there is a need for uplink power control schemes for dualconnectivity.

SUMMARY

Systems and methods relating to uplink power control for a wirelessdevice operating according to a dual connectivity scheme are disclosed.Embodiments of a method of operating a wireless device having a firstlink to a first wireless network node in a wireless communicationsnetwork and a second link to a second wireless network node in thewireless communications network are disclosed. The first and secondlinks are simultaneous or concurrent links to the first and secondwireless network nodes, respectively. In some embodiments, the method ofoperating the wireless device comprises determining a first maximumtransmit power level for the first link from the wireless device to thefirst wireless network node and a second maximum transmit power levelfor the second link from the wireless device to the second wirelessnetwork node and transmitting on the first link and the second linkaccording to the first maximum transmit power level and the secondmaximum transmit power level, respectively. Each of the first maximumtransmit power level and the second maximum transmit power level is afunction of a maximum allowable transmit power level. In this manner,the transmit power of the wireless device does not exceed in maximumallowable transmit power when concurrently transmitting on the first andsecond links.

In some embodiments, a sum of the first maximum transmit power level andthe second maximum transmit power level is less than or equal to themaximum allowable transmit power level.

In some embodiments, the first maximum transmit power level and thesecond maximum transmit power level are statically defined.

In some embodiments, determining the first maximum transmit power leveland the second maximum transmit power level comprises determining thefirst maximum transmit power level and the second maximum transmit powerlevel according to a static definition of the first maximum transmitpower level and the second maximum transmit power level as respectivefractions of the maximum allowable transmit power level.

In some embodiments, determining the first maximum transmit power leveland the second maximum transmit power level comprises, for a particularsubframe of the first link, determining the first maximum transmit powerlevel for the particular subframe of the first link according to astatic definition of the first maximum transmit power level as a firstfraction of a maximum allowable transmit power for the particularsubframe of the first link. Determining the first maximum transmit powerlevel and the second maximum transmit power level further comprises, fora particular subframe of the second link that is either synchronoustransmission with the particular subframe of the first link orasynchronous partially overlapping transmission with the particularsubframe of the first link, determining the second maximum transmitpower level for the particular subframe of the second link according toa static definition of the second maximum transmit power level as asecond fraction of the maximum allowable transmit power for theparticular subframe of the first link. Further, in some embodiments, themaximum allowable transmit power level varies from one subframe toanother subframe. Still further, in some embodiments, the sum of thefirst fraction and the second fraction is less than or equal to 1.

In some embodiments, determining the first maximum transmit power leveland the second maximum transmit power level comprises staticallyassigning values to the first maximum transmit power level and thesecond maximum transmit power level based on one or more of: a number ofuplink antenna ports the wireless device uses over the first and/orsecond links, a number of serving cells configured with uplinktransmission on one or both of the first and second links, and anaverage number of resource blocks the wireless device is expected to beassigned over one or both of the first and second links.

In some embodiments, the first maximum transmit power level and thesecond maximum transmit power level are semi-statically defined.

In some embodiments, determining the first maximum transmit power leveland the second maximum transmit power level comprises, for a particularsubframe of the first link, determining the first maximum transmit powerlevel for the particular subframe of the first link according to asemi-static definition of the first maximum transmit power level as afirst fraction of a maximum allowable transmit power for the particularsubframe of the first link. Determining the first maximum transmit powerlevel and the second maximum transmit power level further comprises, fora particular subframe of the second link that is either synchronoustransmission with the particular subframe of the first link orasynchronous partially overlapping transmission with the particularsubframe of the first link, determining the second maximum transmitpower level for the particular subframe of the second link according toa semi-static definition of the second maximum transmit power level as asecond fraction of the maximum allowable transmit power for theparticular subframe of the first link. Further, in some embodiments, themaximum allowable transmit power level varies from one subframe toanother subframe. Still further, in some embodiments, the sum of thefirst fraction and the second fraction is less than or equal to 1.

In some embodiments, the first maximum transmit power level and thesecond maximum transmit power level are semi-statically definedaccording to a known pattern over a period of time.

In some embodiments, the method of operating the wireless device furthercomprises determining whether a total calculated transmit power levelfor the first and second links is greater than the maximum allowabletransmit power level. Transmitting on the first link and the second linkaccording to the first maximum transmit power level and the secondmaximum transmit power level, respectively, comprises transmitting onthe first link and the second link according to the first maximumtransmit power level and the second maximum transmit power level for oneor both of the links if the total calculated transmit power level forthe first and second links is less than the maximum allowable transmitpower level.

In some embodiments, determining the first maximum transmit power levelfor the first link from the wireless device to the first wirelessnetwork node and the second maximum transmit power level for the secondlink from the wireless device to the second wireless network nodecomprises dynamically determining the first maximum transmit power levelfor the first link from the wireless device to the first wirelessnetwork node and the second maximum transmit power level for the secondlink from the wireless device to the second wireless network node foreach subframe.

In some embodiments, the first and second links have asynchronousoverlapping transmissions, and dynamically determining the first maximumtransmit power level for the first link from the wireless device to thefirst wireless network node and the second maximum transmit power levelfor the second link from the wireless device to the second wirelessnetwork node for each subframe comprises, for a particular subframe ofthe first link, determining the first maximum transmit power level forthe particular subframe of the first link while taking intoconsideration a partial overlap between the particular subframe of thefirst link and an overlapping subframe of the second link.

In some embodiments, the overlapping subframe of the second link is asubframe of the second link that ends at a time that is after thebeginning of the particular subframe of the first link but before an endof the particular subframe of the first link.

In some embodiments, determining the first maximum transmit power levelfor the particular subframe of the first link while taking intoconsideration the partial overlap between the particular subframe of thefirst link and the overlapping subframe of the second link comprisesdetermining the first maximum transmit power level for the particularsubframe of the first link such that a total transmit power of theparticular subframe of the first link and the overlapping subframe ofthe second link is less than or equal to a maximum allowable transmitpower for the particular subframe of the first link.

In some embodiments, the first and second links have asynchronousoverlapping transmissions, and dynamically determining the first maximumtransmit power level for the first link from the wireless device to thefirst wireless network node and the second maximum transmit power levelfor the second link from the wireless device to the second wirelessnetwork node for each subframe comprises determining whether a totaltransmit power across the subframe of the first link and the overlappingsubframe of the second link exceeds a maximum allowable transmit powerlevel for the subframe of the first link and, if the total transmitpower across the subframe of the first link and the overlapping subframeof the second link exceeds the maximum allowable transmit power levelfor the subframe of the first link, scaling a transmit power level foran uplink channel or signal in the subframe of the first link such that,after, the total transmit power across the subframe of the first linkand the overlapping subframe of the second link does not exceed themaximum allowable transmit power level for the subframe of the firstlink.

In some embodiments, the first and second links have asynchronousoverlapping transmissions, and dynamically determining the first maximumtransmit power level for the first link from the wireless device to thefirst wireless network node and the second maximum transmit power levelfor the second link from the wireless device to the second wirelessnetwork node for each subframe comprises, for a particular subframe ofthe first link, determining the first maximum transmit power level forthe particular subframe of the first link while taking intoconsideration a partial overlap between the particular subframe of thefirst link and two consecutive subframes of the second link. In someembodiments, the two overlapping subframes of the second link consistof: (a) a first overlapping subframe that is a subframe of the secondlink that ends at a time that is after the beginning of the particularsubframe of the first link but before an end of the particular subframeof the first link and (b) a second overlapping subframe that is asubframe of the second link that begins at an end of the firstoverlapping subframe and ends at a time that is after the end of theparticular subframe of the first link.

In some embodiments, determining the first maximum transmit power levelfor the particular subframe of the first link while taking intoconsideration the partial overlap between the particular subframe of thefirst link and the two overlapping subframes of the second linkcomprises determining the first maximum transmit power level for theparticular subframe of the first link such that a total transmit powerof the particular subframe of the first link and the first overlappingsubframe of the second link and the total transmit power of theparticular subframe of the first link and the second overlappingsubframe of the second link are both less than or equal to the maximumallowable transmit power for the particular subframe of the first link.

In some embodiments, at least one of the particular subframe of thefirst link and the overlapping subframe of the second link comprises atleast two simultaneous channels, and determining the first maximumtransmit power level for the particular subframe of the first linkcomprises determining the first maximum transmit power level of theparticular subframe of the first link while taking into considerationtransmission power of the at least two simultaneous channels in thepartial overlap between the particular subframe of the first link andthe overlapping subframe of the second link.

In some embodiments, at least one of the first link and the second linkhas multiple serving cells, and determining the first maximum transmitpower level for the particular subframe of the first link comprisesdetermining the first maximum transmit power level of the particularsubframe of the first link while taking into consideration transmissionpower for all of the multiple serving cells in the partial overlapbetween the particular subframe of the first link and the overlappingsubframe of the second link.

In some embodiments, dynamically determining the first maximum transmitpower level for the first link from the wireless device to the firstwireless network node and the second maximum transmit power level forthe second link from the wireless device to the second wireless networknode for each subframe comprises calculating transmission power levelsfor channels transmitted on the first link and the second link andperforming scaling of the transmission power levels for the channelstransmitted on the first link and the second link by applying a firstscaling factor to a channel transmitted on the first link to therebydetermine the first maximum transmit power level such that a totaltransmission power of the wireless device does not exceed a maximumallowable transmit power level.

In some embodiments, the first scaling factor and the second scalingfactor are determined by the wireless device.

In some embodiments, the wireless network nodes are radio access nodesin a cellular communications network.

In some embodiments, a method of operating a wireless device having afirst link to a first wireless network node in a wireless communicationsnetwork and a second link to a second wireless network node in thewireless communications network, where the first link and the secondlink are simultaneous links, comprises assigning a first transmissionpower to the first link and a second transmission power to the secondlink according to a first priority associated with the first link and asecond priority associated with the second link and transmitting on thefirst link and the second link according to the first transmission powerand the second transmission power, respectively.

In some embodiments, assigning the first transmission power to the firstlink before assigning the second transmission power to the second linkif the first priority associated with the first link is higher than thesecond priority associated with the second link.

In some embodiments, assigning the first transmission power to the firstlink and the second transmission power to the second link comprisesassigning a first maximum transmit power level to the first link andassigning a remaining transmit power to the second link if the firstpriority is greater than the second priority and assigning a secondmaximum transmit power level to the second link and assigning aremaining transmit power to the first link if the second priority isgreater than the first priority.

In some embodiments, the method of operating the wireless device furthercomprises associating the first priority with the first link based on achannel to be transmitted on the first link and associating the secondpriority with the second link based on a channel to be transmitted onthe second link.

In some embodiments, assigning the first priority to the first linkbased on the one or more channels to be transmitted on the first linkand assigning the second priority to the second link based on the one ormore channels to be transmitted on the second link comprises assigningthe first priority and the second priority according to predefinedpriorities of a plurality of channel types, the predefined priorities ofthe plurality of channel types being such that: Physical Random AccessChannel (PRACH) has a higher priority than Physical Uplink ControlChannel (PUCCH); PUCCH has a higher priority than PUSCH with UplinkControl Information (UCI); PUSCH with UCI has a higher priority thanPUSCH without UCI; and PUSCH without UCI has a higher priority thanSounding Reference Signal (SRS).

In some embodiments, assigning the first priority to the first linkbased on the one or more channels to be transmitted on the first linkand assigning the second priority to the second link based on the one ormore channels to be transmitted on the second link comprises assigningthe first priority and the second priority according to predefinedpriorities of a plurality of channel types, the predefined priorities ofthe plurality of channel types being such that: PRACH has a higherpriority than PUCCH with Acknowledgement/Non-Acknowledgement (ACK/NACK);PUCCH with ACK/NACK has a higher priority than PUSCH with ACK/NACK;PUSCH with ACK/NACK has a higher priority than PUSCH with Channel StateInformation (CSI) only; PUSCH with CSI only has a higher priority thanPUCCH with CSI only; PUCCH with CSI only has a higher priority than SRS;and SRS has a higher priority than PUSCH with UCI carrying periodic CSIreports triggered by the wireless communications network.

In some embodiments, associating the first transmission power with thefirst link and the second transmission power with the second linkcomprises dropping SRSs from one of the first link and the second linkif a higher priority channel is to be transmitted in the other one ofthe first link and the second link.

In some embodiments, the method of operating the wireless device furthercomprises associating the first priority with the first link based onone or more information types to be transmitted on the first link andassociating the second priority with the second link based on one ormore information types to be transmitted on the second link.

Embodiments of a wireless device operating as described above are alsodisclosed.

Those skilled in the art will appreciate the scope of the presentdisclosure and realize additional aspects thereof after reading thefollowing detailed description of the embodiments in association withthe accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the disclosure, andtogether with the description serve to explain the principles of thedisclosure.

FIG. 1 illustrates a basic Long Term Evolution (LTE) downlink physicalresource;

FIG. 2 is a schematic diagram of an LTE time domain structure;

FIG. 3 illustrates a LTE downlink subframe with a control region ofthree Orthogonal Frequency Division Multiplexing (OFDM) symbols;

FIG. 4 illustrates processing of Layer 1 (L1)/Layer 2 (L2) controlsignaling LTE where, for each Physical Downlink Control Channel (PDCCH),a Cyclic Redundancy Check (CRC) is attached to each Downlink ControlInformation (DCI) message;

FIG. 5 is a schematic diagram illustrating common and User Equipmentdevice (UE) specific search spaces for two UEs;

FIG. 6 is a schematic diagram illustrating resources specificallyassigned for uplink L1/L2 control on LTE Release 8 Physical UplinkControl Channel (PUCCH);

FIG. 7 illustrates Carrier Aggregation (CA);

FIG. 8 illustrates Frequency Division Duplex (FDD) and Time DivisionDuplex (TDD) in a cellular communications network;

FIG. 9 illustrate LTE frame structures for FDD and TDD;

FIG. 10 illustrates seven different TDD configurations allowed in LTE;

FIG. 11 illustrates a scenario where an uplink transmission in one cellinterferes with downlink transmission in a neighboring cell;

FIG. 12 is a schematic diagram illustrating uplink power for a Masterevolved or enhanced Node B (MeNB) and a Secondary evolved or enhancedNode B (SeNB) when a wireless device is operating in a dual-connectivitymode of operation;

FIG. 13 illustrates a cellular communications network enabling uplinkpower control for dual connectivity according to some embodiments of thepresent disclosure;

FIG. 14 is a schematic diagram illustrating static maximum power levelsdefined for the MeNB link and the SeNB link according to someembodiments of the present disclosure;

FIG. 15 is a flow chart that illustrates the operation of a wirelessdevice to operate according to a static configuration of maximumtransmit power levels for the MeNB link and the SeNB link according tosome embodiments of the present disclosure;

FIG. 16 illustrates one of the steps of FIG. 15 in more detail accordingto some embodiments of the present disclosure;

FIG. 17 illustrates the process of FIG. 15 in which the wireless devicedetermines the maximum transmit power levels for the MeNB and SeNB linksby assigning values to the maximum transmit power levels based on adefined criterion;

FIG. 18 illustrates semi-static configuration of the maximum transmitpower levels for the MeNB and SeNB links according to some embodimentsof the present disclosure;

FIG. 19 illustrates one example in which semi-statically defined maximumtransmit power levels for the MeNB and SeNB links can take two or morelevels with a known pattern according to some embodiments of the presentdisclosure;

FIG. 20 illustrates one example in which the maximum transmit powerlevels for the MeNB and SeNB links are applied only when a totalcalculated transmission power across the links exceeds a maximumallowable transmit power level;

FIG. 21 is a flow chart that illustrates the operation of a wirelessdevice to transit uplink transmissions on the MeNB and SeNB linksaccording to a semi-static uplink power control scheme according to someembodiments of the present disclosure;

FIG. 22 illustrates one of the steps of FIG. 21 in more detail accordingto some embodiments of the present disclosure;

FIG. 23 illustrates the process of FIG. 21 in which the wireless devicedetermines the maximum transmit power levels for the MeNB and SeNB linksby semi-statically assigning values to the maximum transmit power levelsbased on a defined criterion according to some embodiments of thepresent disclosure;

FIG. 24 illustrates one example of dynamic configuration of the maximumtransmit power levels for the MeNB and SeNB links according to someembodiments of the present disclosure;

FIG. 25 is a flow chart that illustrates the operation of the wirelessdevice to dynamically determine the maximum transmit power levels forthe MeNB and SeNB links and to transmit uplink transmissions on the linkk according to the determined maximum transmit power levels according tosome embodiments of the present disclosure;

FIG. 26 is a flow chart illustrating the operation of the wirelessdevice according to some dynamic power level configuration embodimentsof the present disclosure;

FIG. 27 is a flow chart that illustrates the operation of the wirelessdevice according to some embodiments in which only the earlier of twooverlapping subframes is considered;

FIGS. 28A and 28B illustrate a process for determining PUCCH transmitpower level according to some embodiments of the present disclosure;

FIG. 29 illustrates a process for determining Physical Uplink SharedChannel (PUSCH) transmit power level according to some embodiments ofthe present disclosure;

FIG. 30 illustrates a process for determining PUSCH transmit power levelaccording to some other embodiments of the present disclosure;

FIG. 31 illustrates a process for determining PUSCH transmit power levelby power scaling across all carriers and links according to someembodiments of the present disclosure;

FIG. 32 is a flow chart that illustrates a procedure that utilizes apower scaling scheme according to some embodiments of the presentdisclosure;

FIG. 33 is a flow chart that illustrates one embodiment of using thethis prioritization of uplink channels to assign the maximum transmitpower levels for the MeNB and SeNB links according to some embodimentsof the present disclosure;

FIG. 34 is a block diagram of a base station according to someembodiments of the present disclosure;

FIG. 35 is a block diagram of a wireless device according to someembodiments of the present disclosure; and

FIG. 36 is a block diagram of a wireless device according to some otherembodiments of the present disclosure.

DETAILED DESCRIPTION

The embodiments set forth below represent information to enable thoseskilled in the art to practice the embodiments and illustrate the bestmode of practicing the embodiments. Upon reading the followingdescription in light of the accompanying drawing figures, those skilledin the art will understand the concepts of the disclosure and willrecognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure and the accompanying claims.

Systems and methods enabling uplink power sharing for dual connectivityare disclosed. Embodiments are described herein in which a maximumuplink (UL) power on each link is configured statically,semi-statically, or dynamically. In general, regardless of theembodiment, uplink power for uplink transmissions from a wireless deviceon two simultaneous links is controlled such that the total uplink powerdoes not exceeds a maximum UL transmission power level while, in someembodiments, taking into account priorities of the two links and/orpriorities of various uplink channels transmitted by the wireless deviceon the two links. Notably, while the embodiments described herein focuson dual connectivity, the embodiments described herein can easily beextended to any number of two or more simultaneous links.

FIG. 13 illustrates a cellular communications network 10 enabling uplinkpower control for dual connectivity according to some embodiments of thepresent disclosure. In the description provided herein, the cellularcommunications network 10 is a Long Term Evolution (LTE) network and, assuch, LTE terminology is oftentimes used. However, the presentdisclosure is not limited to LTE. Rather, the embodiments disclosedherein can be implemented in any suitable wireless system that supportsdual connectivity. As such, a more general term “wireless network node”is used herein to refer to any wireless node in any type of wirelessnetwork (e.g., a radio access node such as a base station or an enhancedor evolved Node B (eNB) in a cellular communications network such as anLTE network, a wireless access node in a local wireless network such asa WiFi network, or the like).

As illustrated, the cellular communications network 10 includes awireless (e.g., a User Equipment device (UE)) having two simultaneouslinks to a Master eNB (MeNB) 14 and a Secondary eNB (SeNB) 16 for uplinktransmissions according to a dual connectivity scheme. The MeNB 14 mayalso be referred to herein as an anchor eNB, and the SeNB 16 may also bereferred to herein as a booster eNB.

As discussed above, one problem with conventional dual connectivityschemes is that the maximum UL transmission power levels for the twolinks are independent from one another. As a result, the total uplinktransmit power of the wireless device 12 may exceed a maximum allowabletransmit power level. The maximum allowable transmit power level is somepredefined power level that is, for example, defined to take intoaccount the maximum UL power allowed in the given cell, the UE powerclass of the wireless device 12, the modulation and transmit bandwidth,compliance with applicable electromagnetic energy absorptionrequirements, and other requirements. As discussed below, systems andmethods are described herein that ensure that the total transmit powerof the wireless device 12 across the two links does not exceed themaximum allowable transmit power level.

In some embodiments, the maximum allowable transmit power level isenforced by defining two static, fixed maximum transmit power levels,P_(MeNB,max) and P_(SeNB,max), for the link to the MeNB 14 and the linkto the SeNB 16, respectively, where

{circumflex over (P)} _(MeNB,max) +{circumflex over (P)} _(SeNB,max)={circumflex over (P)} _(CMAX)(i)  (1)

Here {circumflex over (P)}_(MeNB,max) is the linear value of a maximumoutput power of the wireless device 12 on the MeNB link, {circumflexover (P)}_(SeNB,max) is the linear value of a maximum output power ofthe wireless device 12 on the SeNB link, and {circumflex over(P)}_(CMAX)(i) is the linear value of a configured total maximum outputpower P_(CMAX) of the wireless device 12 for subframe i. The totalmaximum output power {circumflex over (P)}_(CMAX)(i) of the wirelessdevice 12 may be fixed (i.e., the same for all subframes) or may bevariable (e.g., vary between at least some subframes over time).

The static maximum power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) are known to both the MeNB 14 and theSeNB 16 as well as the wireless device 12. The static maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) do not vary with time. In particular, in someembodiments, the static maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) are defined asstatic fractions, or static percentages, of the total maximum outputpower {circumflex over (P)}_(CMAX)(i) of the wireless device 12. Note,however, that while the static fractions do not change over time, thetotal maximum output power {circumflex over (P)}_(CMAX)(i) may, in someembodiments, change over time. As a result, the static maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) may actually vary over time, but the proportions of thetotal maximum output power {circumflex over (P)}_(CMAX)(i) thatcorrespond to the maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) do not change. Onebenefit of using the static maximum power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) is that no explicitsignaling is necessary.

FIG. 14 is a schematic diagram illustrating static maximum power levelsdefined for MeNB and SeNB links according to one example. Asillustrated, in this example, {circumflex over(P)}_(MeNB,max)={circumflex over (P)}_(SeNB,max)=0.5×{circumflex over(P)}_(CMAX)(i). However, this is only an example. As will be appreciatedby one of ordinary skill in the art upon reading this disclosure, thisstatic scenario may more generally be expressed as:

{circumflex over (P)} _(MeNB,max)=γ_(MeNB) {circumflex over (P)}_(CMAX)(i) and

{circumflex over (P)} _(SeNB,max)=γ_(SeNB) {circumflex over (P)}_(CMAX)(i), where

γ_(MeNB)+γ_(SeNB)=1.

The maximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) may be allocated in any suitablemanner. As a first example, the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max)may be allocated as {circumflex over (P)}_(MeNB,max)={circumflex over(P)}_(SeNB,max)=5×{circumflex over (P)}_(CMAX)(i). This allocationtreats the MeNB link and the SeNB link equally in terms of uplink power.As a second example, the MeNB link and the SeNB link may be assignedunequal maximum power levels (i.e., {circumflex over(P)}_(MeNB,max)≠{circumflex over (P)}_(SeNB,max)) according to, e.g., anumber of uplink antenna ports that the wireless device 12 uses over thetwo links, the number of serving cells configured with uplinktransmission on each of the two links, or an average number of ResourceBlocks (RBs) that the wireless device 12 is expected to be assigned overthe two links.

FIG. 15 is a flow chart that illustrates the operation of the wirelessdevice 12 to operate according to a static configuration of the maximumtransmit power levels {circumflex over (P)}_(MeNB,max) and {circumflexover (P)}_(SeNB,max) according to some embodiments of the presentdisclosure. This process simply illustrates some of the embodimentsdescribed above. As illustrated, the wireless device 12 determines themaximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) for the simultaneous links to the MeNB14 and the SeNB 16 (step 100). As discussed above, the maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) may be defined as static fractions, or percentages, ofthe total maximum allowable output power {circumflex over (P)}_(CMAX)(i)of the wireless device 12. These static fractions, which are denoted asγ_(MeNB) and γ_(MeNB) above, may be assigned in any suitable manner(e.g., defined by the wireless device 12 or configured by the MeNB 14).The wireless device 12 transmits uplink transmissions on the MeNB linkand the SeNB link according to the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max),respectively (step 102).

FIG. 16 illustrates step 100 of FIG. 15 in more detail according to someembodiments of the present disclosure. FIG. 16 illustrates the manner inwhich the maximum transmit power level {circumflex over (P)}_(MeNB,max)is determined. The same process can be used to determine the maximumtransmit power level {circumflex over (P)}_(SeNB,max). As illustrated, asubframe index is first initialized (e.g., to a value of 0) (step 200).The wireless device 12 then determines the maximum transmit power level{circumflex over (P)}_(MeNB,max) for subframe i of the link to the MeNB14, which is referred to herein as link k, according to a staticdefinition of the maximum transmit power level {circumflex over(P)}_(MeNB,max) as a fraction of the maximum allowable transmit power{circumflex over (P)}_(CMAX)(i) of the wireless device 12 for subframe i(step 202). The index i is then incremented (step 204), and the processthen returns to step 202. In this manner, the wireless device 12determines the maximum transmit power level {circumflex over(P)}_(MeNB,max) for each subframe i transmitted on link k (i.e., thelink to the MeNB 14).

Using the same process, the wireless device 12 determines the maximumtransmit power level {circumflex over (P)}_(SeNB,max) for each subframei transmitted on link k′ (i.e., the link to the SeNB 16) according to astatic definition of the maximum transmit power level {circumflex over(P)}_(SeNB,max) as a fraction of the maximum allowable transmit powerlevel for the subframe i transmitted on link k′. Notably, for thisdiscussion, it is assumed that the maximum allowable transmit powerlevel {circumflex over (P)}_(CMAX)(i) is determined by taking intoaccount the requirements of subframe i to be transmitted on link k andthe requirements of subframe i to be transmitted on link k′.

As discussed above, in some embodiments, the wireless device 12 assignsthe maximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) based on a criterion such as, forexample, a number of uplink antenna ports that the wireless device 12uses over the two links, the number of serving cells configured withuplink transmission on each of the two links, or an average number ofRBs that the wireless device 12 is expected to be assigned over the twolinks. In this regard, FIG. 17 illustrates the process of FIG. 15 inwhich the wireless device 12 determines the maximum transmit powerlevels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) by assigning (potentially unequal) values to the maximumtransmit power levels {circumflex over (P)}_(MeNB,max) and {circumflexover (P)}_(SeNB,max) based on a defined criterion according to someembodiments of the present disclosure.

More specifically, as illustrated, the wireless device 12 determines themaximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) (step 100) by assigning (potentiallyunequal) values as the maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) based on apredefined criterion (step 300). As discussed above, the predefinedcriterion may be, for example, a number of uplink antenna ports that thewireless device 12 uses over the two links, the number of serving cellsconfigured with uplink transmission on each of the two links, or anaverage number of RBs that the wireless device 12 is expected to beassigned over the two links. In some embodiments, more than one of thesecriteria may be considered. As discussed above, the wireless device 12transmits uplink transmissions on the MeNB link and the SeNB linkaccording to the maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max), respectively (step102).

The embodiments of FIGS. 14 through 17 relate to a static configurationof the maximum transmit power levels {circumflex over (P)}_(MeNB,max)and {circumflex over (P)}_(SeNB,max) for the simultaneous uplinktransmissions to the MeNB 14 and the SeNB 16 according to the dualconnectivity scheme. The discussion will now turn to embodiments inwhich the configuration of the maximum transmit power levels {circumflexover (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) issemi-static.

In some embodiments, instead of assigning static or fixed maximumtransmit power levels, adjustment may be made in a semi-static mannerover time. In some embodiments, the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max)are fixed over a period T (e.g., fractions or percentages of the maximumallowable transmit power level {circumflex over (P)}_(CMAX)(i) over aperiod T are fixed), while the maximum transmit power levels {circumflexover (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) may vary fromone time period T to another (e.g., fractions or percentages of themaximum allowable transmit power level {circumflex over (P)}_(CMAX)(i)may vary from one time period T to another).

Semi-static configuration of the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) isillustrated in FIG. 18. In this example, the maximum transmit powerlevels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) are defined as semi-static fractions, or percentages,γ_(MeNB) and γ_(MeNB), of the maximum allowable transmit power level{circumflex over (P)}_(CMAX)(i). In particular, the maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) during a first time period (T₁), which are denoted as{circumflex over (P)}_(MeNB,max)(T₁) and {circumflex over(P)}_(SeNB,max)(T₁), are:

{circumflex over (P)} _(MeNB,max)(T ₁)=γ_(MeNB)(T ₁){circumflex over(P)} _(CMAX)(i), and

{circumflex over (P)} _(SeNB,max)(T ₁)=γ_(SeNB)(T ₁){circumflex over(P)} _(CMAX)(i),

where γ_(MeNB)(T₁) and γ_(SeNB)(T₁) are the semi-statically definedfractions defined for the first time period T₁ andγ_(MeNB)(T₁)+γ_(SeNB)(T₁)=1. Notably, in this example, it is assumedthat the maximum allowable transmit power level {circumflex over(P)}_(CMAX)(i) is constant during the first time period T₁, but thepresent disclosure is not limited thereto. Similarly, the maximumtransmit power levels {circumflex over (P)}_(MeNB,max) and {circumflexover (P)}_(SeNB,max) during a second time period (T₂), which are denotedas {circumflex over (P)}_(MeNB,max)(T₂) and {circumflex over(P)}_(SeNB,max)(T₂), are:

{circumflex over (P)} _(MeNB,max)(T ₂)=γ_(MeNB)(T ₂){circumflex over(P)} _(CMAX)(i), and

{circumflex over (P)} _(SeNB,max)(T ₂)=γ_(SeNB)(T ₂){circumflex over(P)} _(CMAX)(i),

where γ_(MeNB)(T₂) and γ_(SeNB)(T₂) are the semi-statically definedfractions defined for the second time period T₂ andγ_(MeNB)(T₂)+γ_(SeNB)(T₂)=1. Notably, in this example, it is assumedthat the maximum allowable transmit power level {circumflex over(P)}_(CMAX)(i) is also constant during the second time period T₂, butthe present disclosure is not limited thereto.

The adjustment of the maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) is expected to beslow (i.e., long T) (e.g., the adjustments may be made semi-staticallyvia some semi-statically signaling such as, for example, Radio ResourceControl (RRC) signaling). For example, adjustments may be desired whenthe wireless device 12 moves from an outdoor environment to an indoorenvironment, or vice versa. The benefit is that the maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) can be adjusted over time to match the varyingconditions that the wireless device 12 experiences. In some embodiments,the wireless device 12 performs the semi-static adjustment of themaximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) and signals the resulting values forthe maximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) to the MeNB 14 and the SeNB 16.

In one example embodiment, for a given time period T, the wirelessdevice 12 tracks an average path loss on the MeNB link (i.e., link k)and the SeNB link (link k′). The wireless device 12 then selects{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) inproportion to the path loss on MeNB link and the SeNB link in the nexttime period T. This approach attempts to maintain the same data rateover the two links by allocating proportionally higher power to poorerlinks to compensate for the path loss.

As another example, for a given time period T, the wireless device 12tracks the average path loss on the MeNB link and the SeNB link andselects {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) reversely in proportion to the path loss on the MeNBlink and the SeNB link in the next time period T. This approach attemptsto maximize the aggregate data rate over the two links by allocatingmore power to the link with better channel condition.

In other examples, the wireless device 12 may vary the maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) in time according to other factors such as, for example:(a) uplink interference the wireless device 12 causes, (b) a number ofuplink antenna ports that the wireless device 12 uses over the twolinks, (c) an average number of RBs that the wireless device 12 isassigned, (d) a Quality of Service Class Indicator (QCI) of the bearerson the two links, and/or (e) the number of serving cells configured withuplink transmission on each link.

A variation of the semi-static power allocation is that within theperiod T, the maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) can take two ormore levels with a known pattern. One example is illustrated in FIG. 19.This can be useful for handling Discontinuous Transmission (DTX) of theMeNB 14 or the SeNB 16. For example, the higher level is for thesubframes that the wireless device 12 may have uplink transmission, andthe lower level is for the periods where it is known that there is nouplink transmission. Note that FIG. 19 is only an example. The patternmay have any number of two or more maximum transmit power levels withinthe time period T.

In one alternative embodiment, the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max)for the links are applied only when a total calculated transmissionpower across the uplinks to the MeNB 14 and the SeNB 16 exceeds themaximum allowable transmit power level {circumflex over (P)}_(CMAX)(i).The semi-static maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) are not appliedwhen the total calculated transmission power for the MeNB 14 and theSeNB 16 does not exceed the maximum allowable transmit power level{circumflex over (P)}_(CMAX)(i). One example is given in FIG. 20.

FIG. 21 is a flow chart that illustrates the operation of the wirelessdevice 12 to transmit uplink transmissions on the links to the MeNB 14and the SeNB 16 according to a semi-static uplink power control schemeaccording to some embodiments of the present disclosure. This processcorresponds to at least some of the semi-static embodiments describedabove. As illustrated, optionally (as indicated by dashed lines), thewireless device 12 determines whether a total calculated transmit powerfor the wireless device 12 for the MeNB link and the SeNB link isgreater than the predefined maximum allowable transmit power level{circumflex over (P)}_(CMAX)(i) (step 400). If not, the wireless device12 transmits the uplink transmissions to the MeNB 14 and the SeNB 14over the respective links using the calculated transmit power levels(step 402), and the process then returns to step 400 if there isscheduled UL transmission to MeNB and/or SeNB. The calculated transmitpower levels may be, for example, the transmit power levels calculated(e.g., in the conventional manner) without taking the uplink transmitpower level of one link into consideration when calculating the uplinktransmit power level of the other link (i.e., when calculating thetransmit power levels for the two links separately).

Conversely, if the total calculated transmit power for the wirelessdevice 12 for the MeNB link and the SeNB link is greater than thepredefined maximum allowable transmit power level {circumflex over(P)}_(CMAX)(i), the wireless device 12 determines semi-static maximumtransmit power levels {circumflex over (P)}_(MeNB,max) and {circumflexover (P)}_(SeNB,max) for the MeNB link and the SeNB link, respectively(step 404). As discussed above, in some embodiments, the semi-staticmaximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) are semi-static in that they aredefined according to semi-static fractions γ_(MeNB) and γ_(SeNB) of themaximum allowable transmit power level {circumflex over (P)}_(CMAX)(i),where the maximum allowable transmit power level {circumflex over(P)}_(CMAX)(i) may be static or variable. Notably, in this embodiment,the maximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) (or equivalently the fractions γ_(MeNB)and γ_(SeNB)) are updated for each time period T. The wireless device 12then transmits uplink transmissions to the MeNB 14 and the SeNB 16 overthe corresponding links according to the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max)determined in step 404 (step 406). The process then returns to step 400and is repeated. In some embodiments, the process is repeated for eachsubframe of each of the two links.

FIG. 22 illustrates step 404 of FIG. 21 in more detail according to someembodiments of the present disclosure. FIG. 22 illustrates the manner inwhich the maximum transmit power level {circumflex over (P)}_(MeNB,max)is determined according to a semi-static definition of the maximumtransmit power level {circumflex over (P)}_(MeNB,max) as a fraction ofthe maximum allowable transmit power level {circumflex over(P)}_(CMAX)(i). The same process can be used to determine the maximumtransmit power level {circumflex over (P)}_(SeNB,max). As illustrated, asubframe index is first initialized (e.g., to a value of 0) (step 500).The wireless device 12 then determines the maximum transmit power level{circumflex over (P)}_(MeNB,max) for subframe i of the link to the MeNB14, which is referred to herein as link k, according to a semi-staticdefinition of the maximum transmit power level {circumflex over(P)}_(MeNB,max) as a fraction of the maximum allowable transmit powerlevel {circumflex over (P)}_(CMAX)(i) of the wireless device 12 forsubframe i (step 502). The index i is then incremented (step 504), andthe process then returns to step 502. In this manner, the wirelessdevice 12 determines the maximum transmit power level {circumflex over(P)}_(MeNB,max) for each subframe i transmitted on link k (i.e., thelink to the MeNB 14).

Using the same process, the wireless device 12 determines the maximumtransmit power level {circumflex over (P)}_(SeNB,max) for each subframei transmitted on link k′ (i.e., the link to the SeNB 16) according to asemi-static definition of the maximum transmit power level {circumflexover (P)}_(SeNB,max) as a fraction of the maximum allowable transmitpower level for the subframe i transmitted on link k′. Notably, for thisdiscussion, it is assumed that the maximum allowable transmit powerlevel is determined by taking into account the requirements of subframei to be transmitted on link k and the requirements of subframe itransmitted on link k′.

As discussed above, in some embodiments, the wireless device 12semi-statically assigns the maximum transmit power levels {circumflexover (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) based on acriterion such as, for example, (a) uplink interference the wirelessdevice 12 causes, (b) a number of uplink antenna ports that the wirelessdevice 12 uses over the two links, (c) an average number of RBs that thewireless device 12 is assigned, (d) a QCI of the bearers on the twolinks, and/or (e) the number of serving cells configured with uplinktransmission on each link. In this regard, FIG. 23 illustrates theprocess of FIG. 21 in which the wireless device 12 determines themaximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) by semi-statically assigning(potentially unequal) values to the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max)based on a defined criterion according to some embodiments of thepresent disclosure.

More specifically, as illustrated, the wireless device 12 determines themaximum transmit power levels {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) (step 404) by assigning (potentiallyunequal) semi-static values as the maximum transmit power levels{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max)based on a predefined criterion (step 600). As discussed above, thepredefined criterion may be, for example, (a) uplink interference thewireless device 12 causes, (b) a number of uplink antenna ports that thewireless device 12 uses over the two links, (c) an average number of RBsthat the wireless device 12 is assigned, (d) a QCI of the bearers on thetwo links, and/or (e) the number of serving cells configured with uplinktransmission on each link. In some embodiments, more than one of thesecriteria may be considered.

Thus far, the discussion has focused on static and semi-staticconfiguration of the maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max). The discussionwill now turn to embodiments in which the configuration of the maximumtransmit power levels {circumflex over (P)}_(MeNB,max) and {circumflexover (P)}_(SeNB,max) is dynamic. Like in the embodiments discussedabove, uplink power control is provided for the scenario where thewireless device 12 has two connections, or links, to two network nodes,respectively. Each connection, or link, may be further composed of oneor more serving cells associated with the wireless device 12. Inparticular, a Master Cell Group (MCG) is a group of serving cellsassociated with the MeNB 14, and a Secondary Cell Group (SCG) is a groupof serving cells associated with the SeNB 16.

One example of dynamic configuration of the maximum transmit powerlevels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) is illustrated in FIG. 24. As illustrated, for theasynchronous case where the subframe boundaries on the two links are notaligned, the wireless device 12 determines the maximum transmissionpower {circumflex over (P)}_(MeNB,max) for each subframe i on the MeNBlink (link k) by taking into consideration the used transmission powerin one or more overlapping subframes of the SeNB link (link k′), andvice versa. As illustrated, each subframe on the MeNB link has twooverlapping subframes on the SeNB link. Likewise, each subframe on theSeNB link has two overlapping subframes on the MeNB link. For example,subframe i on the SeNB link is partially overlapped by subframes i andi+1 on the MeNB link. It is important to note here that although forsimplicity, MeNB and SeNB subframes indices are both denoted withvariable ‘i’, ‘i−1’, etc., in general MeNB and SeNB subframes may havesubstantially different subframe numbering and be denoted with twodifferent variables. For example, in general subframes of MeNB isdenoted with index E while subframes of SeNB is denoted with index F. Asdiscussed below in detail, in some embodiments, the transmission poweron both overlapping subframes is taken into consideration. In otherembodiments, the transmission power of only the earlier (in time) of thetwo overlapping subframes is taken into consideration. Further, in someembodiments, the dynamic transmit power control for a particularsubframe of a link k, k′ is performed only if the total calculatedtransmit power for the subframe and its overlapping subframe(s) on theother link exceeds the maximum allowable transmit power for the wirelessdevice 12.

More specifically, in some embodiments, the wireless device 12 followsthe procedure outline below to determine the maximum transmit powerlevels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) that the wireless device 12 uses for uplink transmissionon the MeNB link (denoted as link k) and the SeNB link (denoted as linkk′), respectively. For brevity, it is assumed in the procedure belowthat only one cell in each link has configured uplink, and only oneuplink channel is sent in an uplink subframe (e.g., Physical UplinkControl Channel (PUCCH) or Physical Uplink Shared Channel (PUSCH)).

Step 1: For a subframe i of the link k, the wireless device 12calculates a value {circumflex over (P)}^(k)(i−1) which takes intoaccount the transmission power limits according to the first slot ofsubframe i on link k. Notably, while the term “slot” is used, it isimportant to point out that, as would be understood by one of ordinaryskill in the art, the value {circumflex over (P)}^(k)(i−1) is moreprecisely a maximum transmit power for subframe i of the link k whentaking into account the transmission power of the overlapping subframe ion link k′ (i.e., the earlier of the two subframes on link k′ thatpartially overlap the subframe i on link k). This overlap may be anyamount of overlap depending on the time offset between the subframeboundaries of the two links k and k′. In one specific case or example,the timing offset is such that the overlap between subframe i on link kand the overlapping subframe i on link k′ is equal to a slot. However,the overlap is not limited thereto. As such, in the discussion below,the subframe on the link k′ that is said to overlap the first slot ofsubframe i on link k is to be understood as the subframe on the link k′having: (a) a starting subframe boundary that is before (in time) thestarting subframe boundary of the subframe i on link k and (b) an endingsubframe boundary that is after the starting subframe boundary ofsubframe i on link k but before the ending subframe boundary of subframei on link k. Conversely the subframe on link k′ that is said to overlapthe second slot of subframe i on link k is to understood as the subframeon link k′ having: (a) a starting subframe boundary that is after thestarting subframe boundary of subframe i on link k but before the endingsubframe boundary of subframe i on link k and (b) and ending subframeboundary that is after the ending subframe boundary of subframe i onlink k.

If there is an uplink transmission on the other link k′ overlapping thefirst slot of subframe i on link k, calculate

{circumflex over (P)} ^(k)(i−1)=min({circumflex over (P)} _(SL)^(k)(i),{circumflex over (P)} _(CMAX)(i)−{circumflex over (P)} _(used)^(k′)(i−1)),

where {circumflex over (P)}_(CMAX)(i) refers to the linear value of thetotal configured maximum output power {circumflex over (P)}_(CMAX),{circumflex over (P)}_(used) ^(k′)(i−1) refers to the power level usedby the other link k′ on the subframe that overlaps the first slot of thesubframe i on link k, {circumflex over (P)}_(SL) ^(k)(i) is thecalculated linear power value for the link k assuming link k is thesingle link on which the wireless device 12 has uplink transmission inthe entire duration of subframe i of link k (i.e., assuming non-overlapwith link k′). Thus, {circumflex over (P)}^(k)(i−1) is the lesser of thecalculated linear power value for the link k assuming link k is thesingle link on which the wireless device 12 has uplink transmission inthe entire duration of subframe i of link k and unused portion of themaximum output power {circumflex over (P)}_(CMAX)(i) for subframe i oflink k when considering the used power in the other link k′ on thesubframe that overlaps the first slot of the subframe i on link k. Ifthere is no transmission on the other link (link k′) overlapping thefirst slot of subframe i of link k, {circumflex over (P)}_(used)^(k′)(i−1)=0 and {circumflex over (P)}^(k)(i−1)={circumflex over(P)}_(SL) ^(k)(i).

Step 2: For the subframe i of link k, the wireless device 12 calculatesvalue {circumflex over (P)}^(k)(i) which takes into account thetransmission power limits according to the second slot of subframe i onlink k. If there is an uplink transmission on the other link k′overlapping the second slot of subframe i on link k, {circumflex over(P)}^(k)(i) is calculated as if subframe i of the link k is aligned insubframe boundary with the overlapping subframe of link k′. In thisstep, priority of the uplink channel types between the two links istaken into account. If there is no uplink transmission on the other linkk′ overlapping the second slot of subframe i on link k, {circumflex over(P)}^(k)(i)={circumflex over (P)}_(SL) ^(k)(i).

Step 3: The final power level (i.e., {circumflex over (P)}_(MeNB,max) or{circumflex over (P)}_(SeNB,max)) that the wireless device 12 selectsfor subframe i of link k is {circumflex over (P)}_(*)^(k)(i)=min({circumflex over (P)}^(k)(i−1), {circumflex over(P)}^(k)(i)). This power level represents the total available power forthe given link, i.e. in the example of one MeNB and SeNB. It representsthe total available power for all carriers on either of these links. Forexample, if link k is configured with two uplink component carriers,then the total available power of link k is further shared by thetransmission over the two uplink carriers. Note that if subframeboundary of the two links are aligned (synchronized network with oneTiming Advance Group (TAG)), then the calculation degenerates into{circumflex over (P)}_(*) ^(k)(i)={circumflex over (P)}_(SL) ^(k)(i).This same process is repeated for each subframe of the link k. Likewise,this process is performed to determine P_(SeNB,max) for link k′.

As one simplification, step 2 and step 3 can be omitted. The possibleoverlapping between the second slot of subframe i for link k and thefirst slot of subframe i+1 for link k′ is not considered at all, thenthe final power level degenerates into {circumflex over (P)}_(*)^(k)(i)={circumflex over (P)}^(k)(i−1).

Note also that if Sounding Reference Signal (SRS) on one link overlapswith a higher-priority transmission on the other link, SRS may bedropped rather than being power scaled.

The steps above can be modified to account for the variation where twouplink channels (e.g., PUCCH and PUSCH) are allowed in a same uplinksubframe for a given link. If there is only one uplink channel on link k(i.e., no simultaneous PUSCH and PUCCH), {circumflex over (P)}_(SL)^(k)(i) is the calculated linear power value for the uplink channel(PUSCH or PUCCH) on link k assuming non-overlap with link k′.{circumflex over (P)}_(*) ^(k)(i) is the final power level of the uplinkchannel on link k. This is the scenario assumed in description of steps1 and 2. Conversely, if there are two simultaneous uplink channels onlink k (e.g., simultaneous PUSCH and PUCCH in a subframe), {circumflexover (P)}_(SL) ^(k)(i) is the sum of the calculated linear power valuefor the uplink channels (PUSCH and PUCCH) on link k assuming non-overlapwith link k′. In most cases, {circumflex over (P)}_(SL)^(k)(i)={circumflex over (P)}_(CMAX)(i). {circumflex over (P)}^(k)(i)obtained in step 2 is the maximum power for both uplink channels on linkk. To further allocate {circumflex over (P)}_(*) ^(k)(i) between twosimultaneous uplink channels, the final power level of each individualuplink channel is calculated with the existing formulae taking{circumflex over (P)}_(*) ^(k)(i) as {circumflex over (P)}_(CMAX)(i).

In the description above, it is assumed that each link has only oneserving cell configured with uplink transmission (LTE Release 12).Further details for scenarios where each link configures multiple cellswith uplink transmission (LTE Release 13 and later) are desirable. Steps1-3 above can be modified to account for such case.

In the description above, it is assumed that each link has only oneserving cell configured with uplink transmission. However, steps 1-3above can be extended to the case where each link configures multiplecells with uplink transmissions.

Step 1: For a subframe i of a link k, the wireless device 12 calculatesvalue {circumflex over (P)}_(c) ^(k)(i−1) for serving cell c which takesinto account the transmission power limits according to the first slotof subframe i on link k. If there is an uplink transmission on the otherlink k′ overlapping the first slot of subframe i on link k, calculate

${{{\hat{P}}_{sum}^{k}\left( {i - 1} \right)} = {\min \left( {{\sum\limits_{c}\; {{\hat{P}}_{c}^{k}\left( {i - 1} \right)}},{{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{c^{\prime}}\; {{\hat{P}}_{c^{\prime}}^{k^{\prime}}\left( {i - 1} \right)}}}} \right)}},$

where {circumflex over (P)}_(CMAX)(i) refers to the linear value of thetotal configured maximum output power P_(CMAX) of the wireless device12, P_(c′) ^(k′)(i−1) refers to the power level used by serving cell c′in the other link k′ that overlaps the first slot of the subframe i,{circumflex over (P)}_(c) ^(k)(i−1) is the calculated linear power valuefor serving cell c in the link k assuming link k is the single link onwhich the wireless device 12 has uplink transmission in the entireduration of subframe i (i.e., assuming non-overlap with link k′). Ifthere is no transmission on the other link (link k′) overlapping thefirst slot of subframe i of link k,

${\sum\limits_{c^{\prime}}\; {{\hat{P}}_{c^{\prime}}^{k^{\prime}}\left( {i - 1} \right)}} = {{0\mspace{14mu} {and}\mspace{14mu} {{\hat{P}}_{sum}^{k}\left( {i - 1} \right)}} = {\sum\limits_{c}\; {{{\hat{P}}_{c}^{k}\left( {i - 1} \right)}.}}}$

Step 2: For subframe i of link k, the wireless device 12 calculates avalue {circumflex over (P)}_(sum) ^(k)(i) which takes into account thetransmission power limits according to the second slot of subframe i onlink k. If there is an uplink transmission on the other link k′overlapping the second slot of subframe i on link k, {circumflex over(P)}_(sum) ^(k)(i) is calculated as if subframe i of the link k isaligned in subframe boundary with the overlapping subframe of link k′.In this step, priority of uplink channel types between the two links istaken into account. If there is no uplink transmission on the other linkk′ overlapping the second slot of subframe i on link k,

${{\hat{P}}_{sum}^{k}(i)} = {\sum\limits_{c}\; {{{\hat{P}}_{c}^{k}(i)}.}}$

Step 3: The final total power level that the wireless device 12 uses forsubframe i of link k is {circumflex over (P)}_(*)^(k)(i)=min({circumflex over (P)}_(sum) ^(k)(i−1), {circumflex over(P)}_(sum) ^(k)(i)). If {circumflex over (P)}_(*) ^(k)(i)={circumflexover (P)}_(sum) ^(k)(i−1), the final power level for serving cell c insubframe i of link k is {circumflex over (P)}_(c) ^(k)(i−1) asdetermined in step 1; else if {circumflex over (P)}_(*)^(k)(i)={circumflex over (P)}_(sum) ^(k)(i), the final power levelserving cell c in subframe i of link k is {circumflex over (P)}_(c)^(k)(i) as determined in step 2.

The following is one example of the process described above. For SeNBsubframe i:

-   -   Step 1. {circumflex over (P)}^(SeNB)(i−1)={circumflex over        (P)}_(SL) ^(SeNB)(i), where {circumflex over (P)}_(SL)        ^(seNB)(i) is the calculated power value of subframe i of SeNB        link assuming non-overlap with MeNB;    -   Step 2. {circumflex over (P)}^(SeNB)(i) is calculated assuming        SeNB subframe i is aligned with MeNB subframe i. In this step,        priority of uplink channel types between MeNB and SeNB links is        considered.    -   Step 3. Final power of SeNB subframe i is:

{circumflex over (P)} _(*) ^(SeNB)(i)=min({circumflex over (P)}^(SeNB)(i−1),{circumflex over (P)} ^(SeNB)(i)).

For MeNB subframe i:

-   -   Step 1. {circumflex over (P)}^(MeNB)(i−1)=min ({circumflex over        (P)}_(SL) ^(MeNB)(i),{circumflex over (P)}_(CMAX)(i)−{circumflex        over (P)}_(*) ^(SeNB)(i)), where {circumflex over (P)}_(SL)        ^(MeNB)(i) is the calculated power value of subframe i of MeNB        link assuming non-overlap with SeNB.    -   Step 2. {circumflex over (P)}^(MeNB)(i) is calculated assuming        MeNB subframe i is aligned with SeNB subframe (i+1). In this        step, priority of uplink channel types between MeNB and SeNB        links is considered.    -   Step 3. Final power of MeNB subframe i is

{circumflex over (P)} _(*) ^(MeNB)(i)=min({circumflex over (P)}^(MeNB)(i−1),{circumflex over (P)} ^(MeNB)(i)).

FIGS. 25 and 26 are flow charts that illustrate some embodiments of thedynamic transmit power configuration schemes described above. Morespecifically, FIG. 25 is a flow chart that illustrates the operation ofthe wireless device 12 to dynamically determine the maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and to transmit uplinktransmissions on the link k according to the determined maximum transmitpower level {circumflex over (P)}_(MeNB,max) according to someembodiments of the present disclosure. As illustrated, the wirelessdevice 12 determines the maximum transmit power level {circumflex over(P)}_(MeNB,max) for subframe i of link k taking into consideration theoverlap between subframe i of link k and subframes i and i+1 of link k′using, e.g., any one of the dynamic processes described above (step700). The wireless device 12 transmits an uplink transmission onsubframe i of link k according to the determined maximum transmit powerlevel {circumflex over (P)}_(MeNB,max) (step 702). The wireless device12 then increments the subframe index i (step 704), and the process isthen repeated for the next subframe on link k. This same process mayalso be used in the same manner for the subframes of the link k′.

FIG. 26 is a flow chart illustrating the operation of the wirelessdevice 12 according to some embodiments of steps 1-3 of the dynamicprocess described above. As illustrated, the wireless device 12calculates (or otherwise determines) a first transmit power level forsubframe i of link k considering the overlap between subframe i of linkk and subframe i of link k′ (step 800). The wireless device 12 alsocalculates (or otherwise determines) a second transmit power level forsubframe i of link k considering the overlap between subframe i of linkk and subframe i+1 of link k′ (step 802). The wireless device 12 thendetermines the maximum transmit power level {circumflex over(P)}_(MeNB,max) for subframe i of link k as the minimum of the first andsecond power levels calculated in steps 800 and 802 (step 804). Thisprocess is repeated for each subframe of link k. In the same manner,this process can be used to determine the maximum transmit power level{circumflex over (P)}_(SeNB,max) for each subframe of link k′.

In the embodiments of the dynamic scheme described above, the wirelessdevice 12 takes into consideration the overlap between the subframe i ofone link with both overlapping subframes of the other link. In otherembodiments, only the overlap with the earliest (in time) of the twooverlapping subframes is considered. The other overlapping subframe isnot considered.

In this regard, FIG. 27 is a flow chart that illustrates the operationof the wireless device 12 according to some embodiments in which onlythe earlier of the two overlapping subframes is considered. Morespecifically, FIG. 27 is a flow chart that illustrates the operation ofthe wireless device 12 to dynamically determine the maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and to transmit uplinktransmissions on the link k according to the determined maximum transmitpower level {circumflex over (P)}_(MeNB,max) according to someembodiments of the present disclosure. As illustrated, the wirelessdevice 12 determines the maximum transmit power level {circumflex over(P)}_(MeNB,max) for subframe i of link k taking into consideration onlythe overlap between subframe i of link k and subframe i of link k′(i.e., the earlier of the two overlapping subframes of link k′) using,e.g., any one of the dynamic processes described above (step 900). Thewireless device 12 transmits an uplink transmission on subframe i oflink k according to the determined maximum transmit power level{circumflex over (P)}_(MeNB,max) (step 902). The wireless device 12 thenincrements the subframe index i (step 904), and the process is thenrepeated for the next subframe on link k. This same process may also beused in the same manner for the subframes of the link k′.

The discussion will now turn to some other dynamic uplink power controlschemes according to some other embodiments of the present disclosure.In general, in these embodiments, PUCCH power control and PUSCH powercontrol are provided. The PUSCH transmit power level is scaled if thetotal combined transmit power across both links for all channels isgreater than the maximum allowable transmit power.

PUCCH power control: The transmission power of PUCCH on either the MeNBlink or the SeNB link are, in some embodiments, determined asillustrated in FIGS. 28A and 28B and described as follows. If servingcell c is the primary cell (i.e., the cell of the primary componentcarrier when using carrier aggregation) on the MeNB 14 (step 1000) andif there will be an overlapping transmission in time from the subframei−1 on the SeNB link (i.e., link k′) (step 1002), the P_(PUCCH) transmitpower (i.e., transmit power for PUCCH) for subframe i on the MeNB linkis determined taking into consideration used transmit power in theoverlapping subframe i−1 on link k′ (step 1004). In particular, in someembodiments, the PUCCH transmit power for subframe i on the MeNB link isdetermined according to:

${P_{{PUCCH},{MeNB}}(i)} = {\min {\begin{Bmatrix}{{\min \begin{pmatrix}{{P_{{CMAX},c}(i)},{{P_{CMAX}(i)} - {\sum\limits_{c}\; {P_{{PUSCH},c,{SeNB}}\left( {i - 1} \right)}} -}} \\{P_{{PUCCH},{SeNB}}\left( {i - 1} \right)}\end{pmatrix}},} \\\begin{matrix}{P_{{0{\_ PUCCH}},{MeNB}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} +} \\{{\Delta_{{F\_ PUCCH},{MeNB}}(F)} + {\Delta_{{TxD},{MeNB}}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

In this equation, the top term in the outermost minimization function isto consider the used transmit power in the overlapping subframe i−1 oflink k′ (i.e., the SeNB link). In this example, the used transmit poweris the PUSCH transmit power and the PUCCH transmit power used for theSeNB link. Thus, the top term (which is itself a minimization function)returns the minimum of: (a) the maximum allowable transmit power for thesubframe i and (b) a difference between the maximum allowable transmitpower and the total transmit power already used (both PUSCH and PUCCH)in the overlapping subframe i−1 of the SeNB link. The bottom term in theequation above is the conventional PUCCH transmit power. Thus, the PUCCHtransmit power for subframe i on the MeNB link is the minimum of: (a)P_(CMAX,c)(i), (b) the unused amount of P_(CMAX)(i) when taking intoconsideration the total transmit power already used in the overlappingsubframe i−1 of the SeNB link, and (c) the conventional PUCCH transitpower, which does not take into consideration any overlapping subframesof the SeNB link.

If there is no overlap between subframe i on the MeNB link and subframei−1 on the SeNB link, the wireless device 12 determines the PUCCHtransmit power for subframe i of the MeNB link in a normal orconventional manner (step 1006). In one particular example, the wirelessdevice 12 determines the PUCCH transmit power for subframe i of the MeNBlink as:

${P_{{PUCCH},{MeNB}}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{{0{\_ PUCCH}},{MeNB}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} +} \\{{\Delta_{{F\_ PUCCH},{MeNB}}(F)} + {\Delta_{{TxD},{MeNB}}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

Returning to step 1000, if serving cell c is not the primary cell on theMeNB 14 but is the primary cell on the SeNB 16 (step 1008) and if thethere is an overlap with subframe i−1 on the MeNB link (link k) (step1010), the wireless device 12 determines the P_(PUCCH) transmit power(i.e., transmit power for PUCCH) for subframe i on the SeNB link takinginto consideration used transmit power in the overlapping subframe i−1on link k (step 1012). In particular, in some embodiments, the PUCCHtransmit power for subframe i on the SeNB link is determined accordingto:

${P_{{PUCCH},{SeNB}}(i)} = {\min {\begin{Bmatrix}{{\min \begin{pmatrix}{{P_{{CMAX},c}(i)},{{P_{CMAX}(i)} - {\sum\limits_{c}\; {P_{{PUSCH},c,{MeNB}}\left( {i - 1} \right)}} -}} \\{P_{{PUCCH},{MeNB}}\left( {i - 1} \right)}\end{pmatrix}},} \\\begin{matrix}{P_{{0{\_ PUCCH}},{SeNB}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} +} \\{{\Delta_{{F\_ PUCCH},{SeNB}}(F)} + {\Delta_{{TxD},{SeNB}}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

In this equation, the top term in the outermost minimization function isto consider the used transmit power in the overlapping subframe i−1 oflink k (i.e., the MeNB link). In this example, the used transmit poweris the PUSCH transmit power and the PUCCH transmit power used for theMeNB link. Thus, the top term (which is itself a minimization function)returns the minimum of: (a) the maximum allowable transmit power for thesubframe i and (b) a difference between the maximum allowable transmitpower and the total transmit power already used (both PUSCH and PUCCH)in the overlapping subframe i−1 of the MeNB link. The bottom term in theequation above is the conventional PUCCH transmit power. Thus, the PUCCHtransmit power for subframe i on the SeNB link is the minimum of: (a)P_(CMAX,c)(i), (b) the unused amount of P_(CMAX)(i) when taking intoconsideration the total transmit power already used in the overlappingsubframe i−1 of the MeNB link, and (c) the conventional PUCCH transitpower, which does not take into consideration any overlapping subframesof the MeNB link.

If there is no overlap between subframe i on the SeNB link and subframei−1 on the MeNB link, the wireless device 12 determines the PUCCHtransmit power for subframe i of the SeNB link in a normal orconventional manner (step 1014). In one particular example, the wirelessdevice 12 determines the PUCCH transmit power for subframe i of the SeNBlink as:

${P_{{PUCCH},{SeNB}}(i)} = {\min {\begin{Bmatrix}{{P_{{CMAX},c}(i)},} \\\begin{matrix}{P_{{0{\_ PUCCH}},{SeNB}} + {PL}_{c} + {h\left( {n_{CQI},n_{HARQ},n_{SR}} \right)} +} \\{{\Delta_{{F\_ PUCCH},{SeNB}}(F)} + {\Delta_{{TxD},{SeNB}}\left( F^{\prime} \right)} + {g(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

This process can be repeated by the wireless device 12 for each subframeof both the MeNB link and the SeNB link.

PUSCH power control: The transmission power of PUSCH on either the MeNBlink or the SeNB link are, in some embodiments, determined asillustrated in FIG. 29 and described as follows. In general, FIG. 29illustrates a process in which the PUSCH transmit power of one link isscaled by taking into consideration transmit power in an earlieroverlapping subframe of the other link. If the total transmit power ofthe wireless device 12 for subframe i (the MeNB link or the SeNB link)would exceed the maximum allowable transmit power {circumflex over(P)}_(CMAX)(i) (step 1100) and if there will be an overlappingtransmission in time from subframe i−1 on the SeNB link to subframe i onthe MeNB link (step 1102), the wireless device 12 scales the PUSCHtransmit power level {circumflex over (P)}_(PUSCH,c)(i) for the servingcell c on the MeNB link in subframe i (step 1104). In some embodiments,the wireless device 12 scales the PUSCH transmit power level {circumflexover (P)}_(PUSCH,c)(i) for the serving cell c on the MeNB link insubframe i such that the following condition is satisfied:

${\sum\limits_{c}\; {{w_{1}(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c,{SeNB}}\left( {i - 1} \right)}} - {{\hat{P}}_{{PUCCH},{SeNB}}\left( {i - 1} \right)}} \right) \right)$

where w₁(i) is the scaling factor.

Otherwise, if there will be an overlapping transmission in time fromsubframe i−1 on the MeNB link to subframe i on the SeNB link (step1106), the wireless device 12 scales the PUSCH transmit power level{circumflex over (P)}_(PUSCH,c)(i) for the serving cell c on the SeNBlink in subframe i (step 1108). In some embodiments, the wireless device12 scales the PUSCH transmit power level {circumflex over(P)}_(PUSCH,c)(i) for the serving cell c on the SeNB link in subframe isuch that the following condition is satisfied:

${\sum\limits_{c}\; {{w_{1}(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( \left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c,{MeNB}}\left( {i - 1} \right)}} - {{\hat{P}}_{{PUCCH},{MeNB}}\left( {i - 1} \right)}} \right) \right)$

This process of FIG. 29 illustrates that the PUSCH transmission of thelater subframe i of one link takes at most the leftover power aftersubframe (i−1) of the other link. This process may be useful by itselfif there is no PUCCH in subframe i in parallel with PUSCH of subframe i.In that case, only the overlap needs to be addressed.

The wireless device 12 may determine the PUSCH transmit power in othermanners. For instance, FIG. 30 and the following text describe oneexample of a process by which the wireless device 12 determines thePUSCH transmit power. As illustrated in FIG. 30, if the wireless device12 transmits PUSCH for the serving cell c on either MeNB link or theSeNB link (step 1200), then the PUSCH transmit power levelP_(PUSCH,c)(i) for the wireless device 12 for PUSCH transmission insubframe i for the serving cell c is determined (step 1202). In someembodiments, the PUSCH transmit power level P_(PUSCH,c)(i) for thewireless device 12 for PUSCH transmission in subframe i for the servingcell c is given by:

${P_{{PUSCH},c}(i)} = {\min {\begin{Bmatrix}{{{P_{{CMAX},c}(i)} - {\sum\limits_{c}\; {\cdot {{\hat{P}}_{{PUCCH},c}(i)}}}},} \\\begin{matrix}{{10\; {\log_{10}\left( {M_{{PUSCH},c}(i)} \right)}} + {P_{{O\_ PUSCH},c}(j)} +} \\{{{\alpha_{c}(j)} \cdot {PL}_{c}} + {\Delta_{{TF},c}(i)} + {f_{c}(i)}}\end{matrix}\end{Bmatrix}\lbrack{dBm}\rbrack}}$

wherein {circumflex over (P)}_(PUCCH,c)(i) could also be zero assumingthat there are no ongoing PUCCH transmissions. Another alternative isthat PUSCH transmission on the MeNB link (link k) only considers PUCCHtransmission on the MeNB link, e.g. PUSCH transmissions on the MeNB linkonly consider PUCCH transmissions on the MeNB link. The same may be truefor the SeNB link.

The process of FIG. 30 and the equation above do not address overlapbetween subframe i of the one link with subframe (i−1) of the otherlink. Rather, only the PUCCH and PUSCH in subframe i of the same linkare considered. In the equation above, the first term in theminimization function indicates that the PUCCH has priority over PUSCH.The PUSCH transmit power is at most what is left over after PUCCHtransmission. The second term is the calculated natural, orconventional, PUSCH transmit power level, which is calculated accordingto the needs of PUSCH itself. Taking the minimum of these terms says, ineffect, that if the natural PUSCH power is low, then the natural PUSCHpower will be used. Otherwise, if the natural PUSCH power is high, thenthe PUSCH transmit power will be capped at the amount of power remainingafter allocating power to the PUCCH transmission. The process of FIG. 30is particularly beneficial when there is no overlap with an earliersubframe (i−1) of the other link.

In some embodiments, power scaling across all carriers and links isprovided for dynamic configuration. As illustrated in FIG. 31, in someembodiments, if the total transmit power of the wireless device 12 wouldexceed {circumflex over (P)}_(CMAX)(i) and there will be an overlappingtransmission in time from the subframe i−1 on one link to subframe i ofthe other link (step 1300), the wireless device 12 scales the PUSCHtransmit power level for subframe i of the other link (step 1302). Morespecifically, in some embodiments, if the total transmit power of thewireless device 12 would exceed {circumflex over (P)}_(CMAX)(i) andthere will be an overlapping transmission in time from the subframe i−1on the SeNB link to subframe i on the MeNB link, the wireless device 12scales {circumflex over (P)}_(PUSCH,c)(i) for the serving cell c on theMeNB link (link k) in subframe i such that the following condition issatisfied:

${\sum\limits_{c}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {\left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c,{SeNB}}\left( {i - 1} \right)}} - {{\hat{P}}_{{PUCCH},{SeNB}}\left( {i - 1} \right)}} \right) - {\sum\limits_{c}\; {\cdot {{\hat{P}}_{{PUCCH},c}(i)}}}} \right)$

Otherwise, if there will be an overlapping transmission in time from thesubframe i−1 on the MeNB link to subframe i on the SeNB link, thewireless device 12 scales {circumflex over (P)}_(PUSCH,c,SeNB)(i) forthe serving cell c on the MeNB link (link k) in subframe i such that thefollowing condition is satisfied:

${\sum\limits_{c}\; {{w(i)} \cdot {{\hat{P}}_{{PUSCH},c}(i)}}} \leq \left( {\left( {{{\hat{P}}_{CMAX}(i)} - {\sum\limits_{c}\; {{\hat{P}}_{{PUSCH},c,{MeNB}}\left( {i - 1} \right)}} - {{\hat{P}}_{{PUCCH},{MeNB}}\left( {i - 1} \right)}} \right) - {\sum\limits_{c}\; {\cdot {{\hat{P}}_{{PUCCH},c}(i)}}}} \right)$

This scaling combines the two considerations from above, namely: (a)overlap between subframe i on one link with subframe (i−1) on the otherlink and (b) need of PUCCH in subframe i. In these scaling embodiments,in the event of insufficient power, PUSCH has lower priority, and thePUSCH transmit power level is scaled so that both (a) and (b) are takeninto consideration. Also, note that in the two equations aboveillustrating the scaling, the PUCCH power level is from earlier PUCCHpower level calculations. Hence, if in PUCCH power calculation the UEdetermines that there is no more power left over after PUCCH powercalculation, then the weights w(i) of PUSCH can be set to zero. In thiscase, PUSCH gets no power and is essentially dropped.

The scaling equations can also be explained in the following manner. Theright-hand side of the two preceding equations is a calculation oftransmit power left over after subtracting the transmit power needs ofsubframe i−1 of the other link and the PUCCH transmit power needs ofsubframe i of the link from the maximum allowable transmit power. On theleft-hand sides of the equations, the natural power level of PUSCH(e.g., calculated as the 10 log 10( ) term in the PUSCH power controldescription above) is scaled down by applying weights w(i) so that itdoes not exceed the value calculated on the right-hand side of theequation.

The above scaling embodiments can also be combined with a configurablemaximum transmission power value per link, e.g., the power cannot exceedthis power independent from if there is something transmitted or not onthe other link. Alternatively, the scaling embodiments does consider ifthere is something transmitted or not on the other link, such that themaximum power limitation is only applied in case the UE may exceed themaximum transmission power shared by two links.

In the embodiments above, it was assumed that for any given instant{circumflex over (P)}_(MeNB,max)+{circumflex over(P)}_(SeNB,max)={circumflex over (P)}_(CMAX)(i). Alternatively, themaximum transmit power levels P_(MeNB,max) and {circumflex over(P)}_(SeNB,max) are not defined such that the sum of maximum power mustbe equal to {circumflex over (P)}_(CMAX). For instance, the wirelessdevice 12 could first determine the transmission power for the MeNB linkand the SeNB link separately, assuming non-existence of the otherlink(s). Then, the wireless device 12 could perform power scaling overtwo (or more) simultaneous links if the total power for the two (ormore) links determined in the previous step exceeds the maximum allowedpower {circumflex over (P)}_(CMAX)(i).

FIG. 32 illustrates one embodiment of a procedure that utilizes such ascaling scheme. As illustrated, the wireless device 12 configures themaximum (allowable) transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max) separately (step1400). In this embodiment, the sum of the configured maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) could exceed the maximum allowable transmission powerlevel {circumflex over (P)}_(CMAX) for the wireless device 12. However,one special case is that both {circumflex over (P)}_(MeNB,max) and{circumflex over (P)}_(SeNB,max) are equal to {circumflex over(P)}_(CMAX).

Note that the relative priority between the PUCCH on the MeNB link andthe PUCCH on the SeNB link can be set by the relative values of{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max).In one example, {circumflex over (P)}_(MeNB,max)={circumflex over(P)}_(CMAX), {circumflex over (P)}_(SeNB,max)={circumflex over(P)}_(CMAX). In this case, the wireless device 12 determines the powerof the uplink channel(s) on the MeNB link (as discussed below in step1402) without being limited by the SeNB link and determines the power ofthe uplink channel(s) on the SeNB link (as discussed below in step 1402)without being limited by the MeNB link. The wireless device 12 thenscales the power of uplink channels on the MeNB link and the SeNB linkequally in step 1404 (discussed below) if {circumflex over (P)}_(CMAX)will be exceed by the sum without scaling.

In another example, {circumflex over (P)}_(MeNB,max)={circumflex over(P)}_(CMAX), {circumflex over (P)}_(SeNB,max)=0.5×{circumflex over(P)}_(CMAX). In this case, in step 1402 discussed below, the wirelessdevice 12 determines the transmit power for the uplink channels on theMeNB link without being limited by the SeNB link, whereas the wirelessdevice 12 determines the transmit power for the uplink channels on theSeNB link with the limitation that maximum total power across the SeNBchannels cannot exceed 0.5×{circumflex over (P)}_(CMAX). This biasespower allocation in favor of the MeNB uplink channels if equal scalingis applied in step 1404 (i.e., w_(MeNB)(i)=w_(SeNB)(i)).

After configuring the maximum transmit power levels {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max), the wirelessdevice 12 calculates, or otherwise determines, the transmit power levelsfor the uplink channels to be transmitted on the MeNB link and the SeNBlink (step 1402). In some embodiments, for each link, the calculation ofthe transmit power for the corresponding uplink channels could reuse theprinciples for LTE Release 11 Carrier Aggregation (CA) including channelprioritization as well as the power scaling. Notably, as discussedabove, in some embodiments, the relative priority between the PUCCH onthe MeNB link and the PUCCH on the SeNB link can be set by the relativevalues of {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max). This relative priority may be taken into considerationwhen calculating the transmit power for the uplink channels, asdiscussed above.

The wireless device 12 performs scaling of the transmit power levelsover all (active) channels for both of the links such that the totaltransmit power does not exceed the maximum allowable transmit powerlevel {circumflex over (P)}_(CMAX)(i) (step 1404). In some embodiments,the wireless device 12 performs scaling over all the active channels forboth the MeNB link and the SeNB link so that the total power does notexceed {circumflex over (P)}_(CMAX) according to:

${{\sum\limits_{c}\; {{w_{MeNB}(i)} \cdot {{\hat{P}}_{{MeNB},c}(i)}}} + {\cdot {\sum\limits_{c}\; {{w_{SeNB}(i)} \cdot {{\hat{P}}_{{SeNB},c}(i)}}}}} \leq {{\hat{P}}_{CMAX}(i)}$

where w_(MeNB)(i) and w_(SeNB)(i) are the scaling factors for the MeNBlink and the SeNB link, respectively, and0≦w_(MeNB)(i)≦1,0≦w_(SeNB)(i)≦1. The power scaling for the MeNB link andthe SeNB link could either be same or different. In some embodiments,the ratio of scaling factors for the MeNB link and the SeNB link aresignalled to the wireless device 12. In other embodiments, the scalingfactors are the same and determined by the wireless device 12. Lastly,the wireless device 12 transmits all channels for both the MeNB link andthe SeNB link according to the scaled transmit power levels (step 1406).

The process of FIG. 32 can be combined with either static orsemi-statically defined {circumflex over (P)}_(MeNB,max) and {circumflexover (P)}_(SeNB,max). Handling of unsynchronized subframes between theMeNB link and the SeNB link can be handled by considering overlapping inboth slots or only considering overlapping in first slot.

Thus far, the embodiments described have related to static, semi-static,and dynamic power level configuration when the wireless device 12 isoperating with dual connectivity. In other embodiments, the maximumtransmit power levels {circumflex over (P)}_(MeNB,max) and {circumflexover (P)}_(SeNB,max) are assigned based on priorities assigned to thelinks or to the uplink channels transmitted on the links according tosome embodiments of the present disclosure. In this regarding, in someembodiments, the following uplink transmission priorities, p, areassigned between the different types of uplink channels that can betransmitted on the MeNB link and the SeNB link:

-   -   Physical Random Access Channel (PRACH) (p=1)    -   PUCCH with Uplink Control Information (UCI) (p=2)    -   PUSCH with UCI (p=3)    -   PUSCH without UCI (p=4)    -   SRS (p=5)        Based on these priorities, the maximum transmit power levels        {circumflex over (P)}_(MeNB,max) and {circumflex over        (P)}_(SeNB,max) can be, for example, assigned according to the        following:    -   Share power equally if the transmissions over the two links have        same priority level p;    -   Give full power to a link with higher priority level p, then        give the rest to transmission of next priority;    -   Drop SRS if it overlaps the higher priority channels. Notably,        SRS may not be dropped all the time. For example, if required        SRS power is less than the guaranteed power level of the link,        then SRS may not be dropped.

For two transmissions with UCI, the prioritization can further separateout UCI elements. For example, Hybrid Automatic Repeat Request (HARQ)Acknowledgements/Non-Acknowledgements (ACKs/NACKs), or HARQ-ACK can betreated with higher priority than other UCI elements (Channel StateInformation (CSI)). In this case, the modified priority (high to low)can be defined as:

-   -   PRACH (p=1)    -   PUCCH with HARQ-ACK (p=2)    -   PUSCH with HARQ-ACK (p=3)    -   PUSCH with CSI only (i.e., without HARQ-ACK) (p=4)    -   PUCCH with CSI only (i.e., without HARQ-ACK) (p=5)    -   SRS (p=6)    -   PUSCH with UCI carries aperiodic CSI reports triggered by eNB

FIG. 33 is a flow chart that illustrates one embodiment of using theprioritization of uplink channels to assign the maximum transmit powerlevels P_(MeNB,max) and P_(SeNB,max) according to some embodiments ofthe present disclosure. As illustrated, the wireless device 12 assignsthe maximum transmit power levels P_(MeNB,max) and P_(SeNB,max) for thelinks based on priorities associated with the links (step 1500). Asdiscussed above, the priorities associated with the links is, at leastin some embodiments, based on priorities assigned to, or otherwiseassociated with, the uplink channels to be transmitted on the links,which are referred to herein as active uplink channels for the links.The priorities may be assigned to the uplink channels based on thechannel types or the information, or content, of the channels. Thewireless device 12 transmits uplink transmissions, including the activeuplink channels, on the links according to the assigned maximum transmitpower levels {circumflex over (P)}_(MeNB,max) and {circumflex over(P)}_(SeNB,max) (step 1502).

FIG. 34 is a block diagram of a base station 18 according to someembodiments of the present disclosure. As illustrated, the base station18 includes a baseband unit 20 including one or more processors 22(e.g., Central Processing Unit(s) (CPU(s)), Application SpecificIntegrated Circuit(s) (ASIC(s)), and/or Field Programmable Gate Array(s)(FPGA(s))), memory 24, and a network interface 26 and one or more radiounits 28 including one or more transmitters 30 and one or more receivers32 coupled to one or more antennas 34. In some embodiments, thefunctionality of the base station 18 described herein is implemented insoftware that is stored by the memory 24 and executed by theprocessor(s) 22, whereby the base station 18 operates according to anyof the embodiments described herein.

In some embodiments, a computer program including instructions which,when executed by at least one processor, causes the at least oneprocessor to carry out the functionality of the base station 18according to any of the embodiments described herein is provided. In oneembodiment, a carrier containing the aforementioned computer programproduct is provided. The carrier is one of an electronic signal, anoptical signal, a radio signal, or a computer readable storage medium(e.g., a non-transitory computer readable medium such as the memory 24).

FIG. 35 is a block diagram of a wireless device 36 according to someembodiments of the present disclosure. As illustrated, the wirelessdevice 36 includes one or more processors 38 (e.g., CPU(s), ASIC(s),and/or FPGA(s)), memory 40, and one or more transceivers 42 includingone or more transmitters 44 and one or more receivers 46 coupled to oneor more antennas 48. In some embodiments, the functionality of thewireless device 36 described herein is implemented in software stored inthe memory 40 and executed by the processor(s) 38, whereby the wirelessdevice 36 operates according to any of the embodiments described herein.

In some embodiments, a computer program including instructions which,when executed by at least one processor, causes the at least oneprocessor to carry out the functionality of the wireless device 12according to any of the embodiments described herein is provided. In oneembodiment, a carrier containing the aforementioned computer programproduct is provided. The carrier is one of an electronic signal, anoptical signal, a radio signal, or a computer readable storage medium(e.g., a non-transitory computer readable medium such as the memory 40).

FIG. 36 is a block diagram that illustrates the wireless device 36according to some other embodiments of the present disclosure. Asillustrated, the wireless device 36 includes a power level determinationmodule 50 and a transmit module 52, each of which is implemented insoftware. The power level determination module 50 operates to determine{circumflex over (P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max)according to any of the embodiments described herein. The transmitmodule 52 operates to transmit on the links k and k′ (via an associatedtransmitter(s) of the wireless device 36, which are not shown in FIG.36) in accordance with the determined values for {circumflex over(P)}_(MeNB,max) and {circumflex over (P)}_(SeNB,max).

In one example embodiment, a method is performed at a UE for calculatingpower for a first link for a first subframe. The method comprisesdetermining whether there is an uplink transmission on a second linkoverlapping a first time slot of the first subframe; if a uplinktransmission exists on the second link, calculating power {circumflexover (P)}^(k) (i−1)=min ({circumflex over (P)}_(SL) ^(k)(i),{circumflexover (P)}_(CMAX)(i)−{circumflex over (P)}_(used) ^(k′)(i−1)), where{circumflex over (P)}_(CMAX)(i) refers to the linear value of the UEtotal configured maximum output power level {circumflex over(P)}_(CMAX), {circumflex over (P)}_(used) ^(k′)(i−1) refers to the powerlevel used by the other link k′ that overlaps the first slot of thesubframe i; {circumflex over (P)}_(SL) ^(k)(i) is the calculated linearpower value for the link k assuming link k is the single link that theUE has uplink transmission in the entire duration of subframe i (i.e.,assuming non-overlap with link k′). The method further comprisesdetermining whether there is an uplink transmission on the second linkoverlapping a second slot of the first subframe. If so, the methodcomprises calculating a power {circumflex over (P)}^(k)(i) for a secondsubframe subsequent to the first subframe as if subframe i of the link kis aligned in subframe boundary with the overlapping subframe of linkk′.

The following acronyms are used throughout this disclosure.

-   -   μs Microsecond    -   ACK Acknowledgement    -   AL Aggregation Level    -   ASIC Application Specific Integrated Circuit    -   CA Carrier Aggregation    -   CC Component Carrier    -   CCE Control Channel Element    -   CFI Control Format Indicator    -   CIF Carrier Indicator Field    -   CPU Central Processing Unit    -   CRC Cyclic Redundancy Check    -   C-RNTI Cell Radio Network Temporary Identifier    -   CRS Common Reference Symbol    -   CSI Channel State Information    -   dB Decibel    -   dBm Milli-Decibels    -   DCI Downlink Control Information    -   DFT Discrete Fourier Transform    -   DL PCC Downlink Primary Component Carrier    -   DTX Discontinuous Transmission    -   eNB Enhanced or Evolved Node B    -   ePDCCH Enhanced Physical Downlink Control Channel    -   FDD Frequency Division Duplex    -   FPGA Field Programmable Gate Array    -   GNSS Global Navigation Satellite System    -   HARQ Hybrid Automatic Repeat Request    -   LTE Long Term Evolution    -   MAC Medium Access Control    -   MCG Master Cell Group    -   MeNB Master Enhanced or Evolved Node B    -   MHz Megahertz    -   ms Millisecond    -   NACK Non-Acknowledgement    -   OFDM Orthogonal Frequency Division Multiplexing    -   PCell Primary Cell    -   PDCCH Physical Downlink Control Channel    -   PDSCH Physical Downlink Shared Channel    -   PRACH Physical Random Access Channel    -   PRB Physical Resource Block    -   PUCCH Physical Uplink Control Channel    -   PUSCH Physical Uplink Shared Channel    -   QCI Quality of Service Class Indicator    -   QPSK Quadrature Phase Shift Keying    -   RB Resource Block    -   REG Resource Element Group    -   RLC Radio Link Control    -   RNTI Radio Network Temporary Identifier    -   RRC Radio Resource Control    -   RSRP Reference Signal Received Power    -   SCC Secondary Component Carrier    -   SCG Secondary Cell Group    -   SeNB Secondary Enhanced or Evolved Node B    -   SRS Sounding Reference Signal    -   TAG Timing Advance Group    -   TDD Time Division Duplex    -   TP Transmission Point    -   TPC Transmit Power Control    -   TS Technical Specification    -   UCI Uplink Control Information    -   UE User Equipment    -   UL Uplink    -   UL PCC Uplink Primary Component Carrier    -   VRB Virtual Resource Block

Those skilled in the art will recognize improvements and modificationsto the embodiments of the present disclosure. All such improvements andmodifications are considered within the scope of the concepts disclosedherein and the claims that follow.

1. A method of operating a wireless device having a first link to afirst wireless network node in a wireless communications network and asecond link to a second wireless network node in the wirelesscommunications network, where the first link and the second link aresimultaneous links, comprising: determining a first maximum transmitpower level for the first link from the wireless device to the firstwireless network node and a second maximum transmit power level for thesecond link from the wireless device to the second wireless networknode, where each of the first maximum transmit power level and thesecond maximum transmit power level is a function of a maximum allowabletransmit power level; and transmitting on the first link and the secondlink according to the first maximum transmit power level and the secondmaximum transmit power level, respectively.
 2. The method of claim 1wherein a sum of the first maximum transmit power level and the secondmaximum transmit power level is less than or equal to the maximumallowable transmit power level.
 3. The method of claim 2 wherein thefirst maximum transmit power level and the second maximum transmit powerlevel are statically defined.
 4. The method of claim 2 whereindetermining the first maximum transmit power level and the secondmaximum transmit power level comprises determining the first maximumtransmit power level and the second maximum transmit power levelaccording to a static definition of the first maximum transmit powerlevel and the second maximum transmit power level as respectivefractions of the maximum allowable transmit power level.
 5. The methodof claim 2 wherein determining the first maximum transmit power leveland the second maximum transmit power level comprises: for a particularsubframe of the first link, determining the first maximum transmit powerlevel for the particular subframe of the first link according to astatic definition of the first maximum transmit power level as a firstfraction of a maximum allowable transmit power for the particularsubframe of the first link; and for a particular subframe of the secondlink that is either synchronous transmission with the particularsubframe of the first link or asynchronous partially overlappingtransmission with the particular subframe of the first link, determiningthe second maximum transmit power level for the particular subframe ofthe second link according to a static definition of the second maximumtransmit power level as a second fraction of the maximum allowabletransmit power for the particular subframe of the first link.
 6. Themethod of claim 1 wherein the maximum allowable transmit power levelvaries from one subframe to another subframe.
 7. The method of claim 4wherein the sum of the first fraction and the second fraction is lessthan or equal to
 1. 8. The method of claim 2 wherein determining thefirst maximum transmit power level and the second maximum transmit powerlevel comprises statically assigning values to the first maximumtransmit power level and the second maximum transmit power level basedon one or more factors in a group consisting of: a number of uplinkantenna ports the wireless device uses over the first and/or secondlinks, a number of serving cells configured with uplink transmission onone or both of the first and second links, and an average number ofresource blocks the wireless device is expected to be assigned over oneor both of the first and second links.
 9. The method of claim 2 whereinthe first maximum transmit power level and the second maximum transmitpower level are semi-statically defined.
 10. The method of claim 2wherein determining the first maximum transmit power level and thesecond maximum transmit power level comprises: for a particular subframeof the first link, determining the first maximum transmit power levelfor the particular subframe of the first link according to a semi-staticdefinition of the first maximum transmit power level as a first fractionof a maximum allowable transmit power for the particular subframe of thefirst link; and for a particular subframe of the second link that iseither synchronous transmission with the particular subframe of thefirst link or asynchronous partially overlapping transmission with theparticular subframe of the first link, determining the second maximumtransmit power level for the particular subframe of the second linkaccording to a semi-static definition of the second maximum transmitpower level as a second fraction of the maximum allowable transmit powerfor the particular subframe of the first link.
 11. The method of claim10 wherein the sum of the first fraction and the second fraction is lessthan or equal to
 1. 12. The method of claim 2 wherein the first maximumtransmit power level and the second maximum transmit power level aresemi-statically defined according to a known pattern over a period oftime.
 13. The method of claim 1 wherein transmitting on the first linkand the second link according to the first maximum transmit power leveland the second maximum transmit power level, respectively, comprisestransmitting on the first link according to the first maximum transmitpower level, if the calculated transmit power level for the first linkis greater than the first maximum transmit power level.
 14. The methodof claim 1 wherein determining the first maximum transmit power levelfor the first link from the wireless device to the first wirelessnetwork node and the second maximum transmit power level for the secondlink from the wireless device to the second wireless network nodecomprises dynamically determining the first maximum transmit power levelfor the first link from the wireless device to the first wirelessnetwork node and the second maximum transmit power level for the secondlink from the wireless device to the second wireless network node foreach subframe.
 15. The method of claim 14 wherein the first and secondlinks have asynchronous overlapping transmissions, and dynamicallydetermining the first maximum transmit power level for the first linkfrom the wireless device to the first wireless network node and thesecond maximum transmit power level for the second link from thewireless device to the second wireless network node for each subframecomprises: for a particular subframe of the first link, determining thefirst maximum transmit power level for the particular subframe of thefirst link while taking into consideration a partial overlap between theparticular subframe of the first link and an overlapping subframe of thesecond link.
 16. The method of claim 15 wherein the overlapping subframeof the second link is a subframe of the second link that ends at a timethat is after the beginning of the particular subframe of the first linkbut before an end of the particular subframe of the first link.
 17. Themethod of claim 15 wherein determining the first maximum transmit powerlevel for the particular subframe of the first link while taking intoconsideration the partial overlap between the particular subframe of thefirst link and the overlapping subframe of the second link comprisesdetermining the first maximum transmit power level for the particularsubframe of the first link such that a total transmit power of theparticular subframe of the first link and the overlapping subframe ofthe second link is less than or equal to a maximum allowable transmitpower for the particular subframe of the first link.
 18. The method ofclaim 14 wherein the first and second links have asynchronousoverlapping transmissions, further comprising: determining whether atotal transmit power across a subframe of the first link and anoverlapping subframe of the second link exceeds a maximum allowabletransmit power level for the subframe of the first link; and if thetotal transmit power across the subframe of the first link and theoverlapping subframe of the second link exceeds the maximum allowabletransmit power level for the subframe of the first link, scaling atransmit power level for an uplink channel or signal in the subframe ofthe first link such that, after scaling, the total transmit power acrossthe subframe of the first link and the overlapping subframe of thesecond link does not exceed the maximum allowable transmit power levelfor the subframe of the first link.
 19. The method of claim 14 whereinthe first and second links have asynchronous overlapping transmissions,and dynamically determining the first maximum transmit power level forthe first link from the wireless device to the first wireless networknode and the second maximum transmit power level for the second linkfrom the wireless device to the second wireless network node for eachsubframe comprises: for a particular subframe of the first link,determining the first maximum transmit power level for the particularsubframe of the first link while taking into consideration a partialoverlap between the particular subframe of the first link and twoconsecutive subframes of the second link.
 20. The method of claim 19wherein the two overlapping subframes of the second link consist of: afirst overlapping subframe that is a subframe of the second link thatends at a time that is after the beginning of the particular subframe ofthe first link but before an end of the particular subframe of the firstlink; and a second overlapping subframe that is a subframe of the secondlink that begins at an end of the first overlapping subframe and ends ata time that is after the end of the particular subframe of the firstlink.
 21. The method of claim 19 wherein determining the first maximumtransmit power level for the particular subframe of the first link whiletaking into consideration the partial overlap between the particularsubframe of the first link and the two overlapping subframes of thesecond link comprises: determining the first maximum transmit powerlevel for the particular subframe of the first link such that a totaltransmit power of the particular subframe of the first link and thefirst overlapping subframe that is a subframe of the second link is lessthan or equal to the maximum allowable transmit power for the particularsubframe of the first link.
 22. The method of claim 15 wherein at leastone of the particular subframe of the first link and the overlappingsubframe of the second link comprises at least two simultaneouschannels, and determining the first maximum transmit power level for theparticular subframe of the first link comprises determining the firstmaximum transmit power of the particular subframe of the first linkwhile taking into consideration transmission power of the at least twosimultaneous channels in the partial overlap between the particularsubframe of the first link and the overlapping subframe of the secondlink.
 23. The method of claim 15 wherein at least one of the first linkand the second link has multiple serving cells, and determining thefirst maximum transmit power level for the particular subframe of thefirst link comprises determining the first maximum transmit power of theparticular subframe of the first link while taking into considerationtransmission power for all of the multiple serving cells in the partialoverlap between the particular subframe of the first link and theoverlapping subframe of the second link.
 24. The method of claim 15wherein dynamically determining the first maximum transmit power levelfor the first link from the wireless device to the first wirelessnetwork node and the second maximum transmit power level for the secondlink from the wireless device to the second wireless network node foreach subframe comprises: calculating transmission power levels forchannels transmitted on the first link and the second link; andperforming scaling of the transmission power levels for the channelstransmitted on the first link and the second link by applying a firstscaling factor to a channel transmitted on the first link to therebydetermine the first maximum transmit power level such that a totaltransmission power of the wireless device does not exceed a maximumallowable transmit power level.
 25. The method of any of claim 24wherein the first scaling factor and the second scaling factor aredetermined by the wireless device.
 26. (canceled)
 27. A wireless devicehaving a first link to a first wireless network node in a wirelesscommunications network and a second link to a second wireless networknode in the wireless communications network, where the first link andthe second link are simultaneous links, comprising: means fordetermining a first maximum transmit power level for the first link fromthe wireless device to the first wireless network node and a secondmaximum transmit power level for the second link from the wirelessdevice to the second wireless network node, where each of the firstmaximum transmit power level and the second maximum transmit power levelis a function of a maximum allowable transmit power level; and means fortransmitting on the first link and the second link according to thefirst maximum transmit power level and the second maximum transmit powerlevel, respectively.
 28. A wireless device having a first link to afirst wireless network node in a wireless communications network and asecond link to a second wireless network node in the wirelesscommunications network, where the first link and the second link aresimultaneous links, comprising: a transmitter; at least one processor;and memory containing software instructions executable by the at leastone processor whereby the wireless device is operative to: determine afirst maximum transmit power level for the first link from the wirelessdevice to the first wireless network node and a second maximum transmitpower level for the second link from the wireless device to the secondwireless network node; and transmit, via the transmitter, on the firstlink and the second link according to the first maximum transmit powerlevel and the second maximum transmit power level, respectively, whereeach of the first maximum transmit power level and the second maximumtransmit power level is a function of a maximum allowable transmit powerlevel.
 29. (canceled)
 30. (canceled)
 31. A method of operation of awireless device having a first link to a first wireless network node ina wireless communications network and a second link to a second wirelessnetwork node in the wireless communications network, where the firstlink and the second link are simultaneous links, comprising: assigning afirst transmission power to the first link and a second transmissionpower to the second link according to a first priority associated withthe first link and a second priority associated with the second link;and transmitting on the first link and the second link according to thefirst transmission power and the second transmission power,respectively.
 32. The method of claim 31 wherein the first transmissionpower is assigned to the first link before assigning the secondtransmission power to the second link if the first priority associatedwith the first link is higher than the second priority associated withthe second link.
 33. The method of claim 31 wherein assigning the firsttransmission power to the first link and the second transmission powerto the second link comprises: if the first priority is greater than thesecond priority, assigning a first maximum transmit power level to thefirst link and assigning a remaining transmit power to the second link;and if the second priority is greater than the first priority, assigninga second maximum transmit power level to the second link and assigning aremaining transmit power to the first link.
 34. The method of claim 31further comprising associating the first priority with the first linkbased on a channel to be transmitted on the first link and associatingthe second priority with the second link based on a channel to betransmitted on the second link.
 35. The method of claim 34 whereinassigning the first priority to the first link based on the one or morechannels to be transmitted on the first link and assigning the secondpriority to the second link based on the one or more channels to betransmitted on the second link comprises assigning the first priorityand the second priority according to predefined priorities of aplurality of channel types, the predefined priorities of the pluralityof channel types being such that: Physical Random Access Channel, PRACH,has a higher priority than other channel types.
 36. The method of claim34 wherein assigning the first priority to the first link based on theone or more channels to be transmitted on the first link and assigningthe second priority to the second link based on the one or more channelsto be transmitted on the second link comprises assigning the firstpriority and the second priority according to predefined priorities of aplurality of channel types, the predefined priorities of the pluralityof channel types being such that: Physical Uplink Control Channel,PUCCH, or Physical Uplink Shared Channel, PUSCH, with Hybrid AutomaticRepeat Request, HARQ, -ACK has a higher priority than PUCCH or PUSCHwithout HARQ-ACK.
 37. The method of claim 31 further comprisingassociating the first priority with the first link based on one or moreinformation types to be transmitted on the first link and associatingthe second priority with the second link based on one or moreinformation types to be transmitted on the second link.
 38. The methodof claim 31 wherein assigning the first transmission power to the firstlink and the second transmission power to the second link comprisesdropping Sounding Reference Signals, SRSs, from one of the first linkand the second link if a higher priority channel is to be transmitted inthe other one of the first link and the second link.
 39. (canceled) 40.A wireless device having a first link to a first wireless network nodein a wireless communications network and a second link to a secondwireless network node in the wireless communications network, where thefirst link and the second link are simultaneous links, comprising: meansfor assigning a first transmission power to the first link and a secondtransmission power to the second link according to a first priorityassociated with the first link and a second priority associated with thesecond link; and means for transmitting on the first link and the secondlink according to the first transmission power and the secondtransmission power, respectively.
 41. A wireless device having a firstlink to a first wireless network node in a wireless communicationsnetwork and a second link to a second wireless network node in thewireless communications network, where the first link and the secondlink are simultaneous links, comprising: a transmitter; at least oneprocessor; and memory containing software instructions executable by theat least one processor whereby the wireless device is operative to:assign a first transmission power to the first link and a secondtransmission power to the second link according to a first priorityassociated with the first link and a second priority associated with thesecond link; and transmit, via the transmitter, on the first link andthe second link according to the first transmission power and the secondtransmission power, respectively.
 42. (canceled)
 43. (canceled)